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https://mathoverflow.net/questions/359391/injective-continuous-operators-between-banach-spaces | # Injective continuous operators between Banach spaces
Suppose $$X$$ and $$Y$$ are two infinite dimensional Banach spaces. What can we say about the set of all injective continuous linear operators between $$X$$ and $$Y$$? Is it always nonempty?
• What if $X$ is a non-separable Hilbert space, and $Y$ is a separable one? – erz May 5 '20 at 3:55
• Or more generally, if the Hamel dimension of $X$ is larger than that of $Y$. Then there will be no injective linear operators at all, never mind continuous. – Nate Eldredge May 5 '20 at 5:59
• The answers here show that your second question fails but I think that you have defined an interesting preorder on the family of Banach spaces: $X$ is dominated by $Y$ if such an injection exists. Call the corresponding equivalence relation “weak equivalence”. There is a number of easy pickings (stability properties, etc) that one can quickly deal with but also many interesting questions, in particular, on weak equivalence of specific spaces. I would start with: when is $C(K)$ dominated by (equivalent to) $C(L)$? There is a plethora of such questions for the classical Banach spaces. – user131781 May 5 '20 at 22:12
Of course the dimension is an obvious obstacle, but even if the space have the same cardinality of Hamel bases the answer is no. For example in the paper
A. Avilés, P. Koszmider, A Banach space in which every injective operator is surjective. Bull. Lond. Math. Soc. 45 (2013), no. 5, 1065–1074
the authors constructed an infinitely dimensional Banach space $$X$$ such that if $$T:X\to X$$ is bounded and injective, then $$T(X)=X$$. Therefore if $$Y$$ is a subspace of $$X$$, then one cannot find an injective operator $$T:X\to Y$$.
Piotr Hajłasz' answer nails the problem, however, let me point out that there are easier examples of such pairs of spaces among spaces that have the same density.
Suppose that $$X$$ fails to have a strictly convex renorming. Thus, there is no injective operator $$T$$ from $$X$$ into any space $$Y$$ that is strictly convex, as if it were $$\|x\|^\prime = \|x\| + \|Tx\|$$ would be a strictly convex norm on $$X$$.
Spaces that do not have a strictly convex norm include
• $$X = \ell_\infty^c(\Gamma)$$, the space of all bounded scalar-valued functions on an uncountable set $$\Gamma$$ that have at most countable support (Day);
• $$X = \ell_\infty / c_0$$ (Bourgain).
In the latter case, you may even take $$Y= \ell_\infty$$.
• Is it absolute that there is an example where the density character of both spaces is $\aleph_1$? Are there examples where both spaces are reflexive and have the same density character? – Bill Johnson May 5 '20 at 21:46
• @BillJohnson, for reflexive it is even easier: take $X = \ell_p(\Gamma)$ and $Y=\ell_q(\Gamma)$ for $q>p$. By Pitt's theorem, every operator from $X$ to $Y$ is compact, hence it has separable range. But an injection will be a homeomorphic embedding of the weakly compact unit balls; a contradiction. – Tomasz Kania May 6 '20 at 5:28
• Duh, now. :) (Actually, I was thinking about not having an injective operator in either direction when I asked that stupid question.) – Bill Johnson May 6 '20 at 15:27 | 2021-01-18 05:25:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 20, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9255174398422241, "perplexity": 257.30904053256}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703514121.8/warc/CC-MAIN-20210118030549-20210118060549-00091.warc.gz"} |
https://formulasearchengine.com/wiki/Cost_of_transport | # Cost of transport
The energy cost of transport quantifies the energy efficiency transporting an animal or vehicle from one place to another. It allows for the comparison dissimilar animals or modes of transportation. It has a wide range of applications, from comparing human gaits to observing the change in efficiency of trains over time.
It is calculated in one of two ways, both shown in the following definition:
where ${\displaystyle W}$ is the energy input to the system, which has mass ${\displaystyle m}$, that is used to move the system a distance ${\displaystyle d}$, and ${\displaystyle g}$ is Standard gravity. Alternatively, one can use the power input to the system ${\displaystyle P}$ used to move the system at a constant velocity ${\displaystyle v}$. The cost of transport is non-dimensional.
It is also called specific tractive force or specific resistance (see von Kármán–Gabrielli diagram), or the energy index.[1] When the energy comes from metabolic processes (i.e., for animals), it is often called the metabolic cost of transport.
The metabolic cost of transport for human walking is about 0.1.[2] | 2020-08-11 18:49:27 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 7, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6477085947990417, "perplexity": 562.9537913628714}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439738819.78/warc/CC-MAIN-20200811180239-20200811210239-00304.warc.gz"} |
https://dml.cz/handle/10338.dmlcz/134545 | # Article
Full entry | PDF (0.3 MB)
Keywords:
fuzzy sets; uncertainty; worst scenario method
Summary:
In practice, input data entering a state problem are almost always uncertain to some extent. Thus it is natural to consider a set $\mathcal U_{\mathrm ad}$ of admissible input data instead of a fixed and unique input. The worst scenario method takes into account all states generated by $\mathcal U_{\mathrm ad}$ and maximizes a functional criterion reflecting a particular feature of the state solution, as local stress, displacement, or temperature, for instance. An increase in the criterion value indicates a deterioration in the featured quantity. The method takes all the elements of $\mathcal U_{\mathrm ad}$ as equally important though this can be unrealistic and can lead to too pessimistic conclusions. Often, however, additional information expressed through a membership function of $\mathcal U_{\mathrm ad}$ is available, i.e., $\mathcal U_{\mathrm ad}$ becomes a fuzzy set. In the article, infinite-dimensional $\mathcal U_{\mathrm ad}$ are considered, two ways of introducing fuzziness into $\mathcal U_{\mathrm ad}$ are suggested, and the worst scenario method operating on fuzzy admissible sets is proposed to obtain a fuzzy set of outputs.
References:
[1] Y. Ben-Haim, I. Elishakoff: Convex Models of Uncertainties in Applied Mechanics. Studies in Applied Mechanics, Vol. 25, Elsevier, Amsterdam, 1990.
[2] Y. Ben-Haim: Information Gap Decision Theory. Academic Press, San Diego, 2001. MR 1856675 | Zbl 0985.91013
[3] A. Bernardini: What are the random and fuzzy sets and how to use them for uncertainty modelling in engineering systems? In: Whys and Hows in Uncertainty Modelling, Probability, Fuzziness and Anti-Optimization. I. Elishakoff (ed.), Springer Verlag, Wien-New York, 1999, pp. 63–125. MR 1763168
[4] B. V. Bulgakov: Fehleranheufung bei Kreiselapparaten. Ingenieur-Archiv 11 (1940), 461–469. DOI 10.1007/BF02088988
[5] B. V. Bulgakov: On the accumulation of disturbances in linear systems with constant coefficients. Dokl. Akad. Nauk SSSR 51 (1940), 339–342. (Russian)
[6] J. Chleboun: On a reliable solution of a quasilinear elliptic equation with uncertain coefficients. Nonlinear Anal. Theory Methods Appl. 44 (2001), 375–388. DOI 10.1016/S0362-546X(99)00274-6 | MR 1817101 | Zbl 1002.35041
[7] I. Elishakoff: An idea of the uncertainty triangle. Shock Vib. Dig. 22 (1990), 1. DOI 10.1177/058310249002201001
[8] Whys and Hows in Uncertainty Modelling, Probability, Fuzziness and Anti-Optimization. CISM Courses and Lectures No. 338, I. Elishakoff (ed.), Springer Verlag, Wien, New York, 1999. MR 1763168
[9] R. G. Ghanem, P. D. Spanos: Stochastic Finite Elements: A Spectral Approach. Springer Verlag, Berlin, 1991. MR 1083354
[10] I. Hlaváček: Reliable solutions of problems in the deformation theory of plasticity with respect to uncertain material function. Appl. Math. 41 (1996), 447–466. MR 1415251
[11] I. Hlaváček: Reliable solutions of elliptic boundary value problems with respect to uncertain data. Nonlinear Anal. Theory Methods Appl. 30 (1997), 3879–3890, Proceedings of the WCNA-96. DOI 10.1016/S0362-546X(96)00236-2 | MR 1602891
[12] Uncertainty: Models and Measures. Proceedings of the International Workshop (Lambrecht, Germany, July 22–24, 1996), Mathematical Research, Vol. 99, H. G. Natke, Y. Ben-Haim (ed.), Akademie Verlag, Berlin, 1997. MR 1478000 | Zbl 0868.00034
Partner of | 2021-06-13 11:50:09 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6311322450637817, "perplexity": 3209.7955634277073}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-25/segments/1623487608702.10/warc/CC-MAIN-20210613100830-20210613130830-00216.warc.gz"} |
https://cs.stackexchange.com/questions/123643/boolean-circuit-multigraph | # Boolean circuit multigraph
Let us say that our definition of a circuit is the one of a boolean circuit from [Vollmer]. He uses directed acyclic graphs to represent circuits where the computation nodes are labeled with some functions which come from a set of possible operations (called basis).
Let us say that we only allow the operation $$\land$$ for our circuit (i.e. the basis only consists of $$\land$$). Is $$x \land x$$ a circuit if $$x$$ denotes an input gate? I don't think so, because the input gate $$x$$ is only allowed to occure once in the graph and then we would need two edges to the $$\land$$-node, i.e. we would need a multigraph. A way around would be to force a basis to have an identity operation. For instance using the basis $$\land, id$$ we could of course build the $$x \land x$$ circuit (this is also the case if we can build the identity operation in any other way, e.g. if we have $$\neg$$ in our basis) even though we have to increase the size of the circuit by using $$id$$. It seems very counterintuitive that such a simple circuit is in fact not a circuit over the basis $$\land$$, so is my reasoning correct?
[Vollmer] Heribert Vollmer, Introduction to Circuit Complexity
• It depends on the exact definition. However, let me say that this is an extremely fine and unimportant point. Gates of the form $x \land x$ aren't useful at all. Apr 5 '20 at 11:46
• It would make more sense to allow parallel edges. This is in line with the equivalence to straight-line programs. Apr 5 '20 at 11:47 | 2022-01-18 08:04:37 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 11, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.780788242816925, "perplexity": 228.31909799050342}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320300805.79/warc/CC-MAIN-20220118062411-20220118092411-00665.warc.gz"} |
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ebook esgrima bíblica space in Optimal Dosing in Duodenal UlcerBy Karl E. Peace1550Open score middle. prospective scan commitment. ulcers as Alternative Agents for Gastric Ulcer Prevention and TreatmentBy Ibrahim Abdulkarim Al Mofleh2524Open ebook tar. history as particular fact in the Search of Novel Anti-Ulcerogenic Drugs: continuity of a alternative Medicinal Plant( Maytenus ilicifolia Mart. | 2023-01-28 01:03:01 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.28109267354011536, "perplexity": 13317.0143702394}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499468.22/warc/CC-MAIN-20230127231443-20230128021443-00780.warc.gz"} |
https://fluence.network/docs/book/backend/c_cpp/best_practices.html | # Best practices for C/C++ backend applications
## Request routing
Fluence does not provide a sane request routing yet – only one function can be marked as an entry point. This means that each developer has to independently decide on an input argument format, parse this argument in the entry point function, and call other functions based on the passed action selector.
One option would be to use JSON serialization (for example, provided by parson) to wrap input data.
## Syscall imports
Sometimes imports of syscall could appear in compiled wasm binary. It happens mostly by including some libraries (like stdio.h). Checking the appearance of such imports could be done by translating wasm (binary format) to wast (test format) (e.g. by wabt) and viewing manually for imports. All possible imports are these two:
(import "logger" "write" (func $__write (type 0))) (import "logger" "flush" (func$__flush (type 7)))
They are needed for logger. Also note, almost always imports of syscall could be replaced in text format to empty function.
## Carefully tracking compiler and linker warnings
Generally, it is good idea to investigate all tracking compiler and linker warnings and try to get rid of them. But especially it is important during compilation to Webassembly. Let's review one of these seemingly innocuous warnings that look like this:
wasm-ld: warning: function signature mismatch: qsort
>>> defined as (i32, i32, i32, i32) -> i32 in geo.o
>>> defined as (i32, i32, i32, i32) -> void in /opt/wasi-sdk/share/sysroot/lib/wasm32-wasi/libc.a(qsort.o)
The reason for this error is lacking of #include <stdlib.h> directive. For some reason, a compiler could use signature of this function that returns i32 whereas the original function doesn't return anything. The result is an unnecessary drop instruction after each call of such function. It makes resulted binary incorrect for Wasm validator and, finally, it couldn't be run on Fluence.
## Shrinking app code size
In most cases, there is no need to worry about the size of the generated WebAssembly code. However, there are some common techniques for reducing the WebAssembly package size:
• using -O3 option for aggressive optimization
• using --strip-all options of linker for strip all symbols from generated binary
• not using double float and all functions that receive it as a parameter because it generates a lot of wasm instructions and imports to compiler-rt lib. | 2019-05-24 00:58:11 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.27697092294692993, "perplexity": 4866.013976610883}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-22/segments/1558232257481.39/warc/CC-MAIN-20190524004222-20190524030222-00546.warc.gz"} |
http://nairtl.ie/9qxg5es/c58813-blue-estimator-properties | A vector of estimators is BLUE if it is the minimum variance linear unbiased estimator. 1 Efficiency of MLE Maximum Likelihood Estimation (MLE) is a widely used statistical estimation method. Abbott ¾ PROPERTY 2: Unbiasedness of βˆ 1 and . Since E (b2) = β2, the least squares estimator b2 is an unbiased estimator of β2. Asymptotic Efficiency : An estimator is called asymptotic efficient when it fulfils following two conditions : Save my name, email, and website in this browser for the next time I comment. MSE Estimator : The meaning of MSE is minimum mean square error estimator. It is the combinations of unbiasedness and best properties. If you continue browsing the site, you agree to the use of cookies on this website. As of this date, Scribd will manage your SlideShare account and any content you may have on SlideShare, and Scribd's General Terms of Use and Privacy Policy will apply. Proof: Apply LS to the transformed model. Properties of Least Squares Estimators Each ^ iis an unbiased estimator of i: E[ ^ i] = i; V( ^ i) = c ii ˙2, where c ii is the element in the ith row and ith column of (X0X) 1; Cov( ^ i; ^ i) = c ij˙2; The estimator S2 = SSE n (k+ 1) = Y0Y ^0X0Y n (k+ 1) is an unbiased estimator of ˙2. Sections. Sections . Looks like you’ve clipped this slide to already. This is known as the Gauss-Markov theorem and represents the most important … Thus, OLS estimators are the best among all unbiased linear estimators. A property which is less strict than efficiency, is the so called best, linear unbiased estimator (BLUE) property, which also uses the variance of the estimators. Joshua French 14,925 views. We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. In Section3, we discuss the fuzzy linear regression model based on the author’s previous studies [33,35]. However, because the linear IV model is such an important application in economics, we will give IV estimators an elementary self-contained treatment, and only at the end make connections back to the general GMM theory. best linear unbiased estimator (BLUE), which has the smallest possible variance among the class of unbiased, linear estimators (e.g., Wooldridge 2013, 809–12). Although an unbiased estimator is usually favored over a biased one, a more efficient biased estimator can sometimes be more valuable than a less efficient unbiased estimator. Proposition: The GLS estimator for βis = (X′V-1X)-1X′V-1y. It is linear (Regression model) 2. Search form. by Marco Taboga, PhD. Included are Residential, Utility, Major Industry, Light Industry, Business, Recreational, and Farming. We have observed data x ∈ X which are assumed to be a realisation X = x of a random variable X. The unbiasedness property depends on having many samples of data from the same population. For the validity of OLS estimates, there are assumptions made while running linear regression models.A1. Why BLUE : We have discussed Minimum Variance Unbiased Estimator (MVUE) in one of the previous articles. It is the combinations of unbiasedness and best properties. In most cases, the only known properties are those that apply to large samples. Page; Site ; Advanced 7 of 230. Estimator 3. BLUE. In statistics, best linear unbiased prediction (BLUP) is used in linear mixed models for the estimation of random effects.BLUP was derived by Charles Roy Henderson in 1950 but the term "best linear unbiased predictor" (or "prediction") seems not to have been used until 1962. " Parametric Estimation Properties 5 De nition 2 (Unbiased Estimator) Consider a statistical model. The Gauss-Markov theorem famously states that OLS is BLUE. Generalized least squares. In the following subsection we will consider statistical properties of bias, variance, the issue of bandwidth selection and applications for this estimator. 0 βˆ The OLS coefficient estimator βˆ 1 is unbiased, meaning that . The OLS estimators (interpreted as Ordinary Least- Squares estimators) are best linear unbiased estimators (BLUE). Estimator 3. 2 Properties of the OLS estimator 3 Example and Review 4 Properties Continued 5 Hypothesis tests for regression 6 Con dence intervals for regression 7 Goodness of t 8 Wrap Up of Univariate Regression 9 Fun with Non-Linearities Stewart (Princeton) Week 5: Simple Linear Regression October 10, 12, 2016 4 / 103. Inference on Prediction Properties of O.L.S. 2. 1) 1 E(βˆ =βThe OLS coefficient estimator βˆ 0 is unbiased, meaning that . PROPERTIES OF OLS ESTIMATORS. On one hand, the term “best” means that it has “lowest variance”; on the other, unbiasedness refers to the expected value of the estimator being equivalent to the true value of the parameter (Wooldridge 102). Following points should be considered when applying MVUE to an estimation problem MVUE is the optimal estimator Finding a MVUE requires full knowledge of PDF (Probability Density Function) of the underlying process. Properties of Estimators BS2 Statistical Inference, Lecture 2 Michaelmas Term 2004 Steffen Lauritzen, University of Oxford; October 15, 2004 1. Best Linear Unbiased Estimator | The SAGE Encyclopedia of Social Science Research Methods Search form. 11 See our Privacy Policy and User Agreement for details. However, the Minnesota House of Representatives has a tool that will allow you look up property taxes based on market value, property type, and location. This statistical property by itself does not mean that b2 is a good estimator of β2, but it is part of the story. For Example then . This video explains what is meant by 'OLS estimators are BLUE'. Consider the linear regression model where the outputs are denoted by , the associated vectors of inputs are denoted by , the vector of regression coefficients is denoted by and are unobservable error terms. The results are based on property location, property usage, and assessed property values. If we assume MLR 6 in addition to MLR 1-5, the normality of U Consistency of an estimator means that as the sample size gets large the estimate gets closer and closer to the true value of the parameter. Learn more. Also, the estimate is consistent in any point : (3.62) see e.g. Properties of Least Squares Estimators Each ^ iis an unbiased estimator of i: E[ ^ i] = i; V( ^ i) = c ii˙2, where c ii is the element in the ith row and ith column of (X0X) 1; Cov( ^ i; ^ i) = c ij˙2; The estimator S2 = SSE n (k+ 1) = Y0Y ^0X0Y n (k+ 1) is an unbiased estimator of ˙2. To show this property, we use the Gauss-Markov Theorem. The large sample properties are : Asymptotic Unbiasedness : In a large sample if estimated value of parameter equal to its true value then it is called asymptotic unbiased. The fact that b2 is unbiased does not imply anything about what might happen in just one sample. We assume to observe a sample of realizations, so that the vector of all outputs is an vector, the design matrixis an matrix, and the vector of error termsis an vector. BLUE : An estimator is BLUE when it has three properties : So an estimator is called BLUE when it includes best linear and unbiased property. Get tax estimates instantly to help plan and budget. For example, the maximum likelihood estimator in a regression setup with normal distributed errors is BLUE too, since the closed form of the estimator is identical to the OLS (but as a … Lecture 8: Properties of Maximum Likelihood Estimation (MLE) (LaTeXpreparedbyHaiguangWen) April27,2015 This lecture note is based on ECE 645(Spring 2015) by Prof. Stanley H. Chan in the School of Electrical and Computer Engineering at Purdue University. Inference on Prediction Properties of O.L.S. The Bluebook Repair Estimator enables Real Estate Agents and Inspectors to accurately estimate repair costs for ... From basements to rooftops Bluebook has over 7,800 individual repair and remodel line item costs for a residential property across 42,000+ zip codes in the United States. This presentation lists out the properties that should hold for an estimator to be Best Unbiased Linear Estimator (BLUE). Statistical Properties of the OLS Slope Coefficient Estimator ¾ PROPERTY 1: Linearity of βˆ 1 The OLS coefficient estimator can be written as a linear function of the sample values of Y, the Y Not Found. Sufficient Estimator : An estimator is called sufficient when it includes all above mentioned properties, but it is very difficult to find the example of sufficient estimator. Opener. The paper provides a formula for the L2 estimator of the fuzzy regression model. It is an efficient estimator(unbiased estimator with least variance) 5. This can be used as a general estimate in some cases. With the third assumption, OLS is the Best Unbiased Estimator (BUE), so it even beats non-linear estimators. Researchers have primarily justified LS using the Gauss–Markov theorem because it seems to impart desirable small-sample properties without the overly restrictive assumption of normal errors. PROPERTIES OF OLS ESTIMATORS. Ben Lambert 116,637 views. The Gauss Markov theorem says that, under certain conditions, the ordinary least squares (OLS) estimator of the coefficients of a linear regression model is the best linear unbiased estimator (BLUE), that is, the estimator that has the smallest variance among those that are unbiased and linear in the observed output variables. We have observed data x ∈ X which are assumed to be a realisation X = x of a random variable X. Analysis of Variance, Goodness of Fit and the F test 5. The Gauss-Markov (GM) theorem states that for an additive linear model, and … When some or all of the above assumptions are satis ed, the O.L.S. An estimator is a. function only of the given sample data; this function . It is unbiased 3. The OLS estimator is the vector of regression coefficients that minimizes the sum of squared residuals: As proved in the lecture entitled Li… we respect your privacy and take protecting it seriously, Applications of Differentiation in Economics [Maxima & Minima]. Adhikary et al. It is linear, that is, a linear function of a random variable, such as the dependent variable Y in the regression model. ECONOMICS 351* -- NOTE 4 M.G. Let T be a statistic. PROPERTIES OF Scribd will begin operating the SlideShare business on December 1, 2020 Meaning, if the standard GM assumptions hold, of all linear unbiased estimators possible the OLS estimator is the one with minimum variance and is, therefore, most efficient. Just the first two moments (mean and variance) of the PDF is sufficient for finding the BLUE; Definition of BLUE: Consider a data set $$x[n]= \{ x[0],x[1],…,x[N-1] \}$$ whose parameterized PDF $$p(x;\theta)$$ depends on the unknown parameter $$\theta$$. An estimator is called MSE when its mean square error is minimum. Properties of the Least Squares Estimators Assumptions of the Simple Linear Regression Model SR1. Answered January 12, 2018. with minimum variance) Advantage of BLUE:Needs only 1st and 2nd moments of PDF Mean & Covariance Disadvantages of BLUE: 1. BLUE is an acronym for the following:Best Linear Unbiased EstimatorIn this context, the definition of “best” refers to the minimum variance or the narrowest sampling distribution. Sub-optimal (in general) 2. The formula for calculating MSE is MSE() = var +. Municipal tax = 455 500 x ( 0.451568 / 100) = 2056.89$. The theorem now states that the OLS estimator is a BLUE. Menu. Least Squares Estimators as BLUE - Duration: 7:19. Estimator is Unbiased. Best Linear Unbiased Estimator In: The SAGE Encyclopedia of Social Science Research Methods. 3 Gauss Markov Theorem: OLS estimator is BLUE This theorem states that the OLS estimator (which yields the estimates in vector b) is, under the conditions imposed, the best (the one with the smallest variance) among the linear unbiased estimators of the parameters in vector . ESTIMATORS (BLUE) In addition, the OLS estimator is no longer BLUE. This chapter is devoted to explaining these points. Inference in the Linear Regression Model 4. As such it has a distribution. i.e.. Best Estimator : An estimator is called best when value of its variance is smaller than variance is best. The Gauss-Markov Theorem and “standard” assumptions. RepairBASE allows professionals of all types to create immediate and accurate "contractor quality" estimates detailing the costs of repairs and upgrades required for a property. There are four main properties associated with a "good" estimator. Suppose there is a fixed parameter that needs to be estimated. Properties of the O.L.S. Restrict estimate to be linear in data x 2. Properties of an Estimator. This is a case where determining a parameter in the basic way is unreasonable. two. Parametric Estimation Properties 3 Estimators of a parameter are of the form ^ n= T(X 1;:::;X n) so it is a function of r.v.s X 1;:::;X n and is a statistic. For Example then . Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. In order to create reliable relationships, we must know the properties of the estimators ^ ... (BLUE). The property information on this website is derived from Royal LePage listings and the Canadian Real Estate Association's Data Distribution Facility (DDF). … For example, this can occur when the values of the biased estimator gathers around a number closer to the true value. Unbiasedness is a finite sample property that is not affected by increasing sample size. estimator b of possesses the following properties. 3. i.e., when, Consistency : An estimators called consistent when it fulfils following two conditions. Estimator is Best; So an estimator is called BLUE when it includes best linear and unbiased property. Property tax = Municipal tax + Education tax + Other taxes. The linear regression model is “linear in parameters.”A2. Heteroskedasticity can best be understood visually. Subscribe to our mailing list and get interesting stuff and updates to your email inbox. Take for example: an assesment value of 455 500$, the property tax rate of Toronto: municipal tax of 0.451568%, education tax of 0.161000% and other taxes of 0.002202% for a total in property tax of 0.614770%. These are: 1) Unbiasedness: the expected value of the estimator (or the mean of the estimator) is simply the figure being estimated. Only arithmetic mean is considered as sufficient estimator. Download PDF . Under MLR 1-5, the OLS estimator is the best linear unbiased estimator (BLUE), i.e., E[ ^ j] = j and the variance of ^ j achieves the smallest variance among a class of linear unbiased estimators (Gauss-Markov Theorem). estimator b of possesses the following properties. Under MLR 1-4, the OLS estimator is unbiased estimator. Unbiased Estimator : Biased means the difference of true value of parameter and value of estimator. Find the best one (i.e. Proof under standard GM assumptions the OLS estimator is the BLUE estimator Under the GM assumptions, the OLS estimator is the BLUE (Best Linear Unbiased Estimator). KSHITIZ GUPTA. For example, if statisticians want to determine the mean, or average, age of the world's population, how would they collect the exact age of every person in the world to take an average? Where k are constants. First let us mention that as a consequence of the standard assumption (3.61) the estimate is a density function, i.e. The LS estimator for βin the model Py = PXβ+ Pεis referred to as the GLS estimator for βin the model y = Xβ+ ε. (1984) extended the nonexistence result removing the linearity expression and showed how the optimality properties of classical Horvitz–Thompson Estimator [HTE] pass on to the RR-version given by e above. An estimator, in this case the OLS (Ordinary Least Squares) estimator, is said to be a best linear unbiased estimator (BLUE) if the following hold: 1. Examples: In the context of the simple linear regression model represented by PRE (1), the estimators of the regression coefficients β. i.e . ECONOMICS 351* -- NOTE 3 M.G. Opener. Before jumping into recovering the OLS estimator itself, let’s talk about the Gauss-Markov Theorem. Lack of bias means so that Best unbiased or efficient means smallest variance. Restrict estimate to be unbiased 3. You can also compare taxes over years or across locations. An estimator possesses . by Marco Taboga, PhD. The OLS estimators (interpreted as Ordinary Least- Squares estimators) are best linear unbiased estimators (BLUE). Not Found. Indradhanush: Plan for revamp of public sector banks, revised schedule vi statement of profit and loss, Representation of dalit in indian english literature society, Customer Code: Creating a Company Customers Love, Be A Great Product Leader (Amplify, Oct 2019), Trillion Dollar Coach Book (Bill Campbell), No public clipboards found for this slide. 1. An estimator that is unbiased but does not have the minimum variance is not good. 10:26. Good estimator properties summary - Duration: 2:13. An estimator is said to be unbiased if its bias is equal to zero for all values of parameter θ, or equivalently, if the expected value of the estimator matches that of the parameter.. This means that out of all possible linear unbiased estimators, OLS gives the most precise estimates of and . To examine properties of the sample mean as an estimator for the corresponding population mean, consider the following R example. 1. When the difference becomes zero then it is called unbiased estimator. See our User Agreement and Privacy Policy. BLUE is one such sub-optimal estimate Idea for BLUE: 1. 7:19. 3.6.1 Bias, Variance and Asymptotics. Linear Estimator : An estimator is called linear when its sample observations are linear function. An estimate is unbiased if its expected value equals the true parameter value. This leads to Best Linear Unbiased Estimator (BLUE) To find a BLUE estimator, full knowledge of PDF is not needed. This is known as the Gauss-Markov theorem and represents the most important … Inference in the Linear Regression Model 4. In econometrics, Ordinary Least Squares (OLS) method is widely used to estimate the parameters of a linear regression model. Motivation for BLUE Except for Linear Model case, the optimal MVU estimator might: 1. not even exist 2. be difficult or impossible to find ⇒ Resort to a sub-optimal estimate BLUE is one such sub-optimal estimate Idea for BLUE: 1. Calculation example. (1984) extended the nonexistence result removing the linearity expression and showed how the optimality properties of classical Horvitz–Thompson Estimator [HTE] pass on to the RR-version given by e above. The small-sample properties of the estimator βˆ j are defined in terms of the mean ( ) If you wish to opt out, please close your SlideShare account. The finite-sample properties of the least squares estimator are independent of the sample size. average, and this is one desirable property of an estimator. icon-arrow-top icon-arrow-top. Properties displaying on the realestateview.com.au Price Estimator tool have been created to help people research Australian properties. This property is simply a way to determine which estimator to use. 11. We generate a population pop consisting of observations $$Y_i$$, $$i=1,\dots,10000$$ that origin from a normal distribution with mean $$\mu = 10$$ and variance $$\sigma^2 = 1$$. Statisticians often work with large. 0. and β. Input the cost of the property to receive an instant estimate. Or, enter the phased-in assessed value of a residential property, located on your Property Assessment Notice from the Municipal Property Assessment Corporation […] 2. Notation and setup X denotes sample space, typically either finite or countable, or an open subset of Rk. If you continue browsing the site, you agree to the use of cookies on this website. Hence an estimator is a r.v. Unbiasedness vs … Some of the information available includes a property profile, sales history, rental history, neighbourhood demographics and more. Find the best one (i.e. BLUE: An estimator is BLUE when it has three properties : Estimator is Linear. The OLS estimator is one that has a minimum variance. critical properties. Next, in Section4we prove that the fuzzy least squares estimator shown in the previous section is Best Linear Unbiased Estimator (BLUE). Abbott 1.1 Small-Sample (Finite-Sample) Properties The small-sample, or finite-sample, properties of the estimator refer to the properties of the sampling distribution of for any sample of fixed size N, where N is a finite number (i.e., a number less than infinity) denoting the number of observations in the sample. The properties of the IV estimator could be deduced as a special case of the general theory of GMM estima tors. Thus, estimator performance can be predicted easily by comparing their mean squared errors or variances. Unfortunately at this time, Blue Earth County does not have an online tax estimator. unwieldy sets of data, and many times the basic methods for determining the parameters of these data sets are unrealistic. PROPERTIES OF BLUE • B-BEST • L-LINEAR • U-UNBIASED • E-ESTIMATOR An estimator is BLUE if the following hold: 1. does not contain any . Take the guesswork out of Toronto residential taxes with the Property Tax calculator. This estimator is statistically more likely than others to provide accurate answers. The linear model is one of relatively few settings in which definite statements can be made about the exact finite-sample properties of any estimator. The generalized least squares (GLS) estimator of the coefficients of a linear regression is a generalization of the ordinary least squares (OLS) estimator. Properties of the O.L.S. In the MLRM framework, this theorem provides a general expression for the variance-covariance … Abbott 2. In a simulation experiment concerning the properties of an estimator, the bias of the estimator may be assessed using the mean signed difference. $\begingroup$ The OLS estimator does not need to be the only BLUE estimator. Thus, = (X′P′PX)-1X′P′Py = (X′V-1X)-1X′V-1y ˜ Visit the Property Tax Lookup website. This paper proposes several operations for fuzzy numbers and fuzzy matrices with fuzzy components and discussed some algebraic properties that are needed to use for proving theorems. Finite sample properties of the OLS estimator Christophe Hurlin (University of OrlØans) Advanced Econometrics - HEC Lausanne December 15, 2013 23 / 153. Efficient Estimator : An estimator is called efficient when it satisfies following conditions. This property is called asymptotic property. When some or all of the above assumptions are satis ed, the O.L.S. Notation and setup X denotes sample space, typically either finite or countable, or an open subset of Rk. Lack of bias means so that Best unbiased or efficient means smallest variance. Clipping is a handy way to collect important slides you want to go back to later. Small-Sample Estimator Properties Nature of Small-Sample Properties The small-sample, or finite-sample, distribution of the estimator βˆ j for any finite sample size N < ∞ has 1. a mean, or expectation, denoted as E(βˆ j), and 2. a variance denoted as Var(βˆ j). A fuzzy least squares estimator in the multiple with fuzzy-input–fuzzy-output linear regression model is considered. More generally we say Tis an unbiased estimator of h( ) if and only if E (T) = h( ) for all in the parameter space. A sample is called large when n tends to infinity. Abbott 2. BC Municipalities Property Tax Calculator This calculator can help you determine the property taxes in more than 160 different jurisdictions across British Columbia. Showing the simple linear OLS estimators are unbiased - Duration: 10:26. Then an "estimator" is a function that maps the sample space to a set of sample estimates. T is said to be an unbiased estimator of if and only if E (T) = for all in the parameter space. Restrict estimate to be linear in data x 2. Note that not every property requires all of the above assumptions to be ful lled. The conditional mean should be zero.A4. Where k are constants. Where is another estimator. When the expected value of any estimator of a parameter equals the true parameter value, then that estimator is unbiased. If the form of the heteroskedasticity is known, it can be corrected (via appropriate transformation of the data) and the resulting estimator, generalized least squares (GLS), can be shown to be BLUE. Properties of Estimators BS2 Statistical Inference, Lecture 2 Michaelmas Term 2004 Steffen Lauritzen, University of Oxford; October 15, 2004 1. MSE Estimator : The meaning of MSE is minimum mean square error estimator. Proof under standard GM assumptions the OLS estimator is the BLUE estimator; Connection with Maximum Likelihood Estimation; Wrap-up and Final Thoughts ; 1. unknown . Restrict estimate to be unbiased 3. An estimator is called MSE when its mean square error is minimum. De très nombreux exemples de phrases traduites contenant "estimator blue" – Dictionnaire français-anglais et moteur de recherche de traductions françaises. The accuracy of information is not guaranteed and should be independently verified. ECONOMICS 351* -- NOTE 4 M.G. Some algebraic properties that are needed to prove theorems are discussed in Section2. Adhikary et al. You can change your ad preferences anytime. ECONOMICS 351* -- NOTE 3 M.G. Even if the PDF is known, […] Linear Estimator : An estimator is called linear when its sample observations are linear function. Encyclopedia. Analysis of Variance, Goodness of Fit and the F test 5. An estimator of is usually denoted by the symbol . Thus, the LS estimator is BLUE in the transformed model. So an estimator is called BLUE when it includes best linear and unbiased property. Bluebook's RepairBASE provides a national "cost to repair and maintain" data standard and property solution for the preservation of bank owned and managed properties. OLS estimators are linear functions of the values of Y (the dependent variable) which are linearly combined using weights that are a non-linear function of the values of X (the regressors or explanatory variables). 0) 0 E(βˆ =β• Definition of unbiasedness: The coefficient estimator is unbiased if and only if ; i.e., its mean or expectation is equal to the true coefficient β parameters. DDF references real estate listings held by brokerage firms other than Royal LePage and its franchisees. The main idea of the proof is that the least-squares estimator is uncorrelated with every linear unbiased estimator of zero, i.e., with every linear combination a 1 y 1 + ⋯ + a n y n {\displaystyle a_{1}y_{1}+\cdots +a_{n}y_{n}} whose coefficients do not depend upon the unobservable β {\displaystyle \beta } but whose expected value is always zero. Show page numbers . Thus, OLS estimators are the best among all unbiased linear estimators. Linear regression models have several applications in real life. Note that not every property requires all of the above assumptions to be ful lled. Now customize the name of a clipboard to store your clips. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Like all other linear estimators, the ultimate goal of OLS is to obtain the BLUE Let us first agree on a formal definition of BLUE. There is a random sampling of observations.A3. Page 9 of 15 pages S3: Efficiency A Necessary Condition for Efficiency -- Unbiasedness The small-sample property of efficiency is defined only for unbiased estimators. One of the most important properties of a point estimator is known as bias. Gauss Markov theorem.
## blue estimator properties
Casio Ap-470 Review, Apple Grape Pasta Salad, Rasakadali Banana In English, Ranch Homes For Sale In Pa, Healthy Spinach Soup, Admiration Barberry Thorns, Data Science For Business Ebook, Protein Peanut Butter, Spiritfarer Spirits List, Kenai Fjords National Park Facts, | 2021-03-07 02:20:08 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5281000137329102, "perplexity": 1149.6822241036778}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178376006.87/warc/CC-MAIN-20210307013626-20210307043626-00407.warc.gz"} |
https://www.physicsforums.com/threads/arc-length-question.274726/ | # Arc Length Question
1. Nov 24, 2008
### kevtimc
1. The problem statement, all variables and given/known data
y = (2/3) * (x^2 - 1) ^ (3/2) 1 <= x <= 3
Length = ?
2. Relevant equations
L = $$\int\sqrt{1 + (dy/dx)^2} dx$$
3. The attempt at a solution
dy/dx y = (2/3) * (x^2 - 1) ^ (3/2) =
2x * sqrt(x - 1)
Any ideas for a proper substitution? The answer on wolfram seems ridiculous.
Last edited: Nov 24, 2008
2. Nov 24, 2008
### Citan Uzuki
Hmm... it seems wolfram is being ridiculous on this problem. But you don't need a substitution here. Observe that the derivative is 2x√(x² - 1), not 2x√(x - 1). So once you go back and do the arithmetic correctly, you will find that 1 + (dy/dx)² is the square of a polynomial (specifically, it is (2x² - 1)²). After that, this problem should be a piece of cake.
3. Nov 24, 2008
### kevtimc
I actually knew it was x2, just a typing error. I actually got (2x2 - 1)2
the first time I calculated it, but I didn't get the right answer for the definite integral at 1 through 3 (15.333).
My solution:
(2x)^2 * (x^2 - 1) + 1 = 4x^4 - 4x^2 + 1 = (2x^2 - 1)^2
= (2/3) * x3 -x + C ] (1-3) = 15.333 Nevermind . . .
Last edited: Nov 24, 2008
4. Nov 24, 2008
### Citan Uzuki
Glad you figured it out. It looks like you have the theory right, and were just getting caught up with typos.
5. Nov 25, 2008
### kevtimc
Story of my mathematical life. | 2017-10-22 08:48:39 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5623600482940674, "perplexity": 1565.3667723752924}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187825154.68/warc/CC-MAIN-20171022075310-20171022095310-00875.warc.gz"} |
http://jadetex.sourceforge.net/?source=navbar | ## 2. Installation
### 2.1. Introduction
This documents is based on a note by FC describing his experience installing JadeTeX with OpenJade 1.3 and teTeX 1.06 (on Unix). It has since been expanded and checked by SR and SP. It is aimed to people who have perhaps some experience using TeX and LaTeX, enough to write up technical reports using simple macros, but know little or nothing about format files or the particulars of the TeX distribution structure, and consequently have a rough time with JadeTeX…
This document relates to JadeTeX version 2.11 or later.
To use JadeTeX, you first of all should compile and install OpenJade. The resulting openjade executable, used with the -t tex flag, will format an SGML/XML file and yield a TeX output file. Using jadetex or pdfjadetex, you can transform this into DVI or PDF; from DVI, you can use a program like dvips to get PostScript output. This note describes how to build and install the former two programs, jadetex and pdfjadetex.
### 2.2. Increasing TeX capacities
The TeX output file uses a macro package, JadeTeX, built on top of LaTeX, just as LaTeX is a macro package sitting on top of plain TeX. It is probably possible to just stick an \input at the top of your .tex file and use the JadeTeX macros this way, but that would be slow since TeX would need to parse and compile the macro definitions every time you format your .tex file. So what we do instead is to use TeX (actually, initex) to read in the LaTeX format, followed by the JadeTeX package, once, and dump the compiled image to what is called a ‘format file.’ This is the same way that LaTeX is usually employed. Once the format file is built and installed, it is easy to arrange for TeX to read it in quickly and automatically when you process a .tex file.
But, as ever, there are complications, relating to TeX's capacity restrictions. TeX is designed to use a fixed amount of resources to process documents; for example, there is a maximum number of strings that can be allocated, and a maximum stack size. If a processing run exceeds the default limits, TeX will complain and refuse to continue. Unfortunately, OpenJade's TeX backend tends to exceed these default limits.
Fortunately, though, there is no need to recompile your TeX binary. If you are using teTeX (or any other Web2c-based distribution) there will be a file called texmf.cnf in your installation which sets the capacity parameters and is consulted every time TeX is run. By adding the right parameter settings here, you can ensure that JadeTeX will be unlikely to run out of memory.
Where is texmf.cnf? You can find it in the web2c directory under your texmf tree... which begs the question, where is texmf? The most straightforward way to find it is to make sure all the TeX executables are in your PATH; then do: kpsewhich -expand-var '\$TEXMFMAIN' /usr/share/texmf/web2c/texmf.cnf and it will respond with the location of your texmf tree. As you can see, it is also known as \$TEXMFMAIN, which is how I shall refer to it in the sequel.
If for some reason kpsewhich is not in your PATH, and you don't know where it is, here are some likely locations:
• /usr/share/texmf
• /usr/local/share/texmf
• /usr/local/teTeX/texmf
• /usr/local/lib/teTeX/texmf
• /usr/local/lib/texmf
• /usr/lib/texmf
• /usr/lib/teTeX/texmf
In a minute we are going to modify texmf.cnf to increase the capacities, then build the JadeTeX format file and install the JadeTeX executable(s). You may have a command hugelatex, a version of latex with greater capacity settings than the usual one, which is named simply latex. If so, build your format file using hugelatex rather than latex, so that JadeTeX inherits the `huge' settings. Otherwise, make sure your latex is big. In addition, if you make any changes to the literate source of the JadeTeX macro package (see below), a normal latex may not do.
First we need to update texmf.cnf to ensure that latex really is huge. Take a look at the top of the file. It will probably say:
%original texmf.cnf -- runtime path configuration file for kpathsea.
% (If you change or delete `original' on the previous line, the
% distribution won't install its version over yours.)
If it says
% TeX Live texmf.cnf
then you can skip all this and proceed to the next section, as TeX Live is already set up for JadeTeX
If you have an `original', follow those directions and delete the string original to ensure that future upgrades won't obliterate your changes.
In the latter half of the file, you will find the capacity settings, which look something like this:
pool_size = 125000
pool_size.context = 750000
Here, pool_size is the name of the parameter in both cases, but the second one is qualified with .context, which indicates that this setting will be preferred when using the ConTeXt macro package. We need to make similar accomodations not only for latex but also jadetex and pdfjadetex. Unfortunately, we don't know the minimal required values for every parameter and some of these values are probably ridiculously high, but no matter ...
% latex settings
main_memory.latex = 1100000
param_size.latex = 1500
stack_size.latex = 1500
hash_extra.latex = 15000
string_vacancies.latex = 45000
pool_free.latex = 47500
nest_size.latex = 500
save_size.latex = 5000
pool_size.latex = 500000
max_strings.latex = 55000
font_mem_size.latex= 400000
Add these to the end of the file, or wherever makes you happy.
Now let's build some format files. Under \$TEXMFMAIN/tex/latex/config, you will find the files necessary to rebuild latex. Copy them somewhere temporary and go there:
cp -R /usr/share/texmf/tex/latex/config /tmp
cd /tmp/config
Now do this:
tex -ini -progname=latex latex.ini
This will produce a file latex.fmt in the same directory. Rename this to latex.fmt, then become root and put it in \$TEXMFMAIN/web2c. This is where all the format files are kept. (You can delete the other copied files from config afterwards.)
mv latex.fmt /usr/share/texmf/web2c
Now just create a symbolic link from tex to latex:
ln -s /usr/bin/tex /usr/local/bin/latex
When tex is invoked, it looks at the name X it was invoked with, then loads the format file X.fmt from \$TEXMFMAIN/web2c before it starts processing the document. So creating this symbolic link is all that is needed to create the latex executable.
### 2.3. Creating the format files
Next, take a look at your OpenJade distribution. Under the directory dsssl you will find the files necessary to build jadetex and pdfjadetex, including a Makefile. Now become root and just do:
make install
This creates jadetex.fmt and pdfjadetex.fmt, puts them in \$TEXMFMAIN/web2c for you (using kpsewhich to find \$TEXMFMAIN), and installs a few other auxiliary files under \$TEXMFMAIN/tex/jadetex.
All that's left to do is to create the links:
(changing the location of the binary directory to wherever your TeX is) and run mktexlsr so that your TeX distribution becomes aware of the newly installed files in \$TEXMFMAIN/tex/jadetex.
mktexlsr
### 2.4. Testing the installation
Finally, test your installation using the demonstration files in that directory:
openjade -t tex -d demo.dsl demo.sgm
You're done!
I installed JadeTeX, but when I run it, it complains that a file named unicode.sty (or dsssl.def, etc) can't be found. What did I do wrong?
You didn't run the mktexlsr, so kpathsea doesn't know about the newly installed files.
I don't like JadeTeX's default behavior in some situations. How do I modify it?
If for some reason you want to modify the JadeTeX macro package, modify the file jadetex.dtx. This is the literate source for the format file and other files installed under \$TEXMFMAIN/tex/jadetex. To format it, use latex:
You will get tons of overfull hboxes but if you are using a nice big latex, it will work. Formatting the batch file jadetex.ins will produce stripped sources (dsssl.def and jadetex.ltx), which can be compiled into format files as before:
What fonts can I use?
Following is the names of the font families supported at the time of writing. Of course you must actually have these fonts installed to format the document (but not to produce the TeX output).
• Arial
• Helvetica
• Palatino
• Bookman
• Courier
• Symbol
• Wingdings
• WingDings
• LucidaSans
• LucidaBright
• Savoy
• ACaslon
• Caslon
• Formata
• FranklinGothic
• OCRAbyBT
• AGaramond
• Avant-Garde
• Courier-New
• New-Century-Schoolbook
• Times-Roman
• Times-New-Roman
• Times-NR-MT
• Courier-New
• Zapf-Dingbats
• Gill-Sans
• iso-serif
• iso-sanserif
• iso-monocase
• LetterGothic12PitchBT
• Monospace821
• OCRB10PitchBT
• OCR-A
• OCR-B-10PitchBT
• Computer-Modern-Typewriter
• Computer-Modern-Sans
• Computer-Modern
• Computer-Modern-Caps-And-Small-Caps
Why doesn't hyphenation work?
Remember that your text must be fully justified (quadding: #t), hyphenation must be on, hyphenation?: #t, and a current language must be selected (e.g., language: 'EN) for JadeTeX to perform hyphenation.
I'm using Norman Walsh's DocBook stylesheets and my footnotes are coming up at the end of the document rather than at the foot of each page. Why? | 2014-04-24 09:09:06 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9607373476028442, "perplexity": 4420.416082858385}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-15/segments/1398223206118.10/warc/CC-MAIN-20140423032006-00607-ip-10-147-4-33.ec2.internal.warc.gz"} |
https://www.shaalaa.com/question-bank-solutions/answer-the-following-question-indian-rupee-plunged-to-an-all-time-low-of-7448-against-the-us-dollar-the-economic-times-in-light-of-the-above-report-discuss-the-impact-of-the-determination-equilibrium-income-short-run-effect-autonomous-change-aggregate-demand-income-output_106770 | # Answer the Following Question. "Indian Rupee (₹) Plunged to an All-time Low of ₹ 74.48 Against the Us Dollar ($)". − the Economic Times in Light of the Above Report, Discuss the Impact of the - Economics Advertisement Remove all ads Advertisement Remove all ads Answer in Brief Answer the following question. "Indian Rupee (₹) plunged to an all-time low of ₹ 74.48 against the US Dollar ($)".
− The Economic Times
In light of the above report, discuss the impact of the situation on Indian Imports.
#### Solution
Indian Rupee is depreciating against the US Dollar since it is given that " Indian Rupee (₹) plunged to an all-time low of ₹ 74.48 against the US Dollar (\$)".A high exchange rate makes the imports more expensive. Consequently, a rise in the exchange rate implies a reduction in the demand for imports and vice-versa.
When imports fall, net exports (Exports - Imports) of a country rise. The given figure explains this process as follows:
Suppose the initial equilibrium income is given by Ye that corresponds to a trade balance equal to Ytb. With the rise in the net export demand, the aggregate demand curve DD shifts upwards to DD' such that the new equilibrium is established at point E' and the equilibrium income rises to Y'.
In the lower panel due to the fall in the imports, the net export rises and the net export curve shifts upwards from NX to NX'.At the new level of income, the net exports is represented by the vertical distance AE' which are necessarily positive (because the total demand curve DD' lies above the aggregate demand curve AD). Thus, with a fall in imports, there is a trade surplus. This trade surplus is represented in the lower panel by the vertical length DF.
Concept: Determination of Equilibrium Income in the Short Run - Effect of an Autonomous Change in Aggregate Demand on Income and Output
Is there an error in this question or solution? | 2022-06-25 01:57:50 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5393981337547302, "perplexity": 2247.3375540927323}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-27/segments/1656103033925.2/warc/CC-MAIN-20220625004242-20220625034242-00448.warc.gz"} |
https://dsp.stackexchange.com/tags/system-identification/hot?filter=year | # Tag Info
7
Short answer: You can't. If an attacker can insert a signal that covers the whole bandwidth (e.g. a white signal, or at least one that has no spectral zeros) into the system (and he can do that over an arbitrarily long time, or add up observations), they will get an output, and can through the magic of correlation get the impulse response.
4
The system $$y[n] = x[n] \star (u[n]-u[n-2])$$ where $u[n]$ is the unit step function, has memory. Indeed the system is equivalent to $$y[n] = x[n] \star ( \delta[n] + \delta[n-1] ) \implies y[n] = x[n] + x[n-1]$$ and as it's clear from the given I/O relationship, the current value of the output $y[n]$, depends on the values input $x[n]$ at other times ...
3
Long answer: Let's model the information flow from your "hidden" IIR $X$ to your observable output $Y$ as $$X \longrightarrow Y$$ Then, we call the amount of information you get per observation the *mutual information $I(X;Y)$; that information is the reduction of uncertainty about $X$ to be achieved by observing $Y$. We call the expected uncertainty ...
3
It is very strange phenomena that one object is completely dropped out of attention of researchers. It is Urysohn operator. First of all Urysohn is equivalent to multiple parallel Hammersteins and Urysohn followed by static nonlinearity is a model of any deterministic dynamic object, it maps any given input to any provided output. I obtained Ph.D. in ...
2
You can use pyvib to do frequency based subspace identification. Beware that there is no estimation of the initial state. It is possible to do optimization of the identified model, if the data is not perfectly linear. See the implemenentation, maybe you can use it, in case you want to do your own implementation. Somewhat incomplete example. Take a look at ...
2
The easiest is Urysohn adaptive filter: http://www.ezcodesample.com/UAF/UAF.html It can build nonlinear model by few lines of code. The theoretical details can be found here http://www.ezcodesample.com/NAF/index.html The site has downloadable coding sample. Besides UAF, the other common methods are: Kernel LMS, Voltera LMS, Neural networks, Point cloud. ...
1
Looks like you've done a lot of work on your projects. As @MarcusMüller said, by far the majority of people start with ReLU and go from there. It doesn't have the "vanishing gradient" problem that tanh has for example. All your questions are open ended but common for designing neural networks. There are so many "nobs to turn" to try and make your network be ...
1
True that a chirp signal helps to get the FRF, but every time we change the frequency we can't reach the steady state, so this will cause bias in the estimation. As an advice try to use the multisine excitation, they are more suitable for such cases.
1
SIDPAC is a freely available program from software.nasa.gov. It is targeted toward aircraft system id problems however the underlying methods are applicable to other problem types.
1
I believe the point of feeding white noise into the system is for the filter to adapt its coefficients before actually generating the signal $x[k]$. This would mean there are two "operating modes" for the system: coefficient adapting mode (in which white noise, a broadband signal, is used to adapt the filter to the feedback path), and performing mode (where ...
1
You do get a time-invariant response. Your code produces the same output for all three signals. In particular, it produces the same output for $y(\sigma^T\{x(t)\}))$ as for $\sigma^T\{y(x(t))\}$ (plots 2 and 3 in your code). It is hard to see in your case because you have shifted the signal $3\cdot 2\pi$ in time. Whats a cosine shifted by $6\pi$? The same ...
1
The chosen cost function is the mean squared error, i.e., the integral over a squared magnitude of the difference between frequency responses. The function $$E(e^{j\omega})=H(e^{j\omega})-\frac{B(e^{j\omega})}{A(e^{j \omega})}\tag{1}$$ depends on frequency, so you can't minimize it directly, unless you want to minimize it for exactly one frequency $\omega$,...
1
First of all, I want to thank Fat32 and Hilmar for answering the question. I'm sorry I couldn't answer before, because I had some external problems to solve. Finally I was able to solve the problem by using the reverse time property of the Zeta-Transform (despite having some difficulties with the initial conditions). Consider a non-minimum phase system ...
1
Here is one way to think about it: Let's say you have an unstable transfer function, which is unstable because of a single pole outside the unit circle. We can write this as $$H_0(z)=H_{stable}(z) \cdot \frac{1}{1-z^{-1} \cdot p}$$ That's a cascade of the stable and unstable part. Now we can multiply this with a unity filter that has a pole and zero at the ...
1
An unstable system can be stablized by all-pass decomposition for exampe, but simply constructing the anti-causal impulse respone extension will not provide the same output; so I think it's not possible, but I'm not rigorous at this point. Following just shows why. Assume that your unstable and causal IIR filter has the impulse response $h_+[n]$ and by ...
1
Convolution is a linear operator. As such, it can be, at least theoretically, inverted. But it is infinite in length, and in coefficient amplitude precision. Which, in real world practice, cannot be reached. So the balance resides in what you call "protecting", and there might be some "privacy by design" possibilities: if the algorithm is a mere ...
Only top voted, non community-wiki answers of a minimum length are eligible | 2019-12-10 05:09:30 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7478882074356079, "perplexity": 612.7661951008868}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540525821.56/warc/CC-MAIN-20191210041836-20191210065836-00549.warc.gz"} |
http://mathematica.stackexchange.com/questions/3719/how-to-generate-a-real-time-stream-of-data | # How to generate a real-time stream of data?
I'm experimenting with Inversion-of-Control (callback) programming patterns, and I would like a way to generate streams of data at specified real-time intervals. I came up with the illustrated way to use Animate (or Manipulate) to do it, and that's fine for experiments with the notebook front end, but I would like to have pure-code solutions I could put in a .m package. As always, I will be grateful for any hints, advice, and solutions!
-
Have you looked at RunScheduledTask and related functions? – Heike Mar 30 '12 at 16:04
Not till now :) Post this as answer and I'll mark it such! – Reb.Cabin Mar 30 '12 at 17:25
I've posted my answer. – Heike Mar 30 '12 at 20:15
You could use RunScheduledTask or its relatives for this. For example, to append a random integer to catch once every two seconds you could do something like
catch = {};
You could also use CreateScheduledTask which is similar to RunScheduledTask except that the task won't be started automatically after it's been created. You'll have to use StartScheduledTask to start it manually.
To start and stop the scheduled task you can use StartScheduledTask[task] and StopScheduledTask[task], respectively, and RemoveScheduledTask[task] will remove the scheduled task once you're done with it. | 2015-04-25 12:32:01 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.43439897894859314, "perplexity": 1854.764745535858}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246649234.62/warc/CC-MAIN-20150417045729-00128-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://fractalforums.org/fractal-image-of-the-month/70/fractal-image-of-the-month-discussion-thread/150/60 | ### Poll
#### what sort of image contest do you find appealing enough to participate in regularly
one program, unaltered, random topic
minimal alteration allowed, topic via poll from list generated from user suggestions
completely random, as is now, no topic
some of the above
all of the above
### Fractal image of the month - Discussion thread
• 110 Replies
• 3675 Views
0 Members and 1 Guest are viewing this topic.
#### Sabine62
• Fractal Freak
• Posts: 663
• It's just a jump to the left...
#### Re: Fractal image of the month - Discussion thread
« Reply #60 on: October 29, 2018, 12:06:34 PM »
Gerrit already said in the October-thread that sending a reminder to vote a few days earlier would be a good idea and I agree! Tonight at 12pm I got a reminder to vote and at 3.30 this morning I got: And the winners are...
And I only checked my mail at 8.00 this morning
Maybe a message could be placed on the Home-page alerting users to the competition? Blinking? :}:}:}
I'd really love to see more participants, especially since we have members with such varied fractal interests
Update: hmmm, themes?? Halloween? Colour? Fuzz? Or would that be too childish? (not for me! )
To thine own self be true
• Moderator
• Posts: 285
#### Re: Fractal image of the month - Discussion thread
« Reply #61 on: October 29, 2018, 12:10:10 PM »
I didn't send a reminder, maybe that goes automatic?
Anyway, every month till now, I put on the last day a call to vote but this time I didn't, for all the other times maybe one or two persons voted, no more than that. So only a reminder is not enough to get people to participate I think. A call on the main page would maybe be a good idea?
#### Sabine62
• Fractal Freak
• Posts: 663
• It's just a jump to the left...
#### Re: Fractal image of the month - Discussion thread
« Reply #62 on: October 29, 2018, 07:57:08 PM »
Code: [Select]
Topic unlocked: Fractal Image of the month - October 2018 - Please vote! A topic you are watching has been unlocked by Caleidoscope.
That's an e-mail timed at 00:03 last night, auto-notification
So indeed, you're not sending anything... My bad!
I agree we should get a notification to vote also on the Home-page
#### Fraktalist
• Strange Attractor
• Posts: 1160
#### Re: Fractal image of the month - Discussion thread
« Reply #63 on: October 29, 2018, 08:22:17 PM »
dunno how to put such a reminder on the home page.
but if someone just posts a short "vote now" in the last days to just keep the topic up and in view, that should be enough.
sorry I'm not more active myself right now, life got very chaotic here with lots of big changes that take up nearly all of my time.
hope this will calm down in the next weeks.
#### Sabine62
• Fractal Freak
• Posts: 663
• It's just a jump to the left...
#### Re: Fractal image of the month - Discussion thread
« Reply #64 on: October 29, 2018, 09:05:17 PM »
Argghhh no flashing banners like in the merry early nineties?
The messages... ehm... I need to be the remindee, not the reminder
Good luck with everything, Fraktalist, take your time!
• 3f
• Posts: 1922
#### Re: Fractal image of the month - Discussion thread
« Reply #65 on: October 30, 2018, 04:08:11 AM »
I didn't send a reminder, maybe that goes automatic?
Anyway, every month till now, I put on the last day a call to vote but this time I didn't, for all the other times maybe one or two persons voted, no more than that. So only a reminder is not enough to get people to participate I think. A call on the main page would maybe be a good idea?
Probably not many people check this website every day, so maybe a "call for votes" say 5 day before the deadline?
You could also perhaps add some motivational stuff about how good it is to vote, though I wouldn't know what that would be
Or put up a list of people that voted with a thank you to shame the non-voters?
Or make the vote obligatory, and get suspended when you don't vote but have accessed the website withing the voting period.
Not sure how I can get more silly...
• Moderator
• Posts: 285
#### Re: Fractal image of the month - Discussion thread
« Reply #66 on: October 30, 2018, 03:26:50 PM »
Probably not many people check this website every day, so maybe a "call for votes" say 5 day before the deadline?
You could also perhaps add some motivational stuff about how good it is to vote, though I wouldn't know what that would be
Or put up a list of people that voted with a thank you to shame the non-voters?
Or make the vote obligatory, and get suspended when you don't vote but have accessed the website withing the voting period.
Not sure how I can get more silly...
Yeah, I can do that. I think the best thing is to make a little change every day to keep it in the picture :0o I can try that, if I have the time and don't forget it I'm not sure it will be very helpful. Maybe to make it more known on the internet, on social media... get more members and get more participants. Maybe that is not even a bad idea? I think a shame-list is not such a friendly idea Maybe we can sell the virtual tomatoes and get some money for FF Nor the more dictatorial option
But thank you for your input. Much appreciated, at least you come up with some ideas
« Last Edit: November 26, 2018, 11:56:33 PM by Caleidoscope »
• Moderator
• Posts: 285
#### Re: Fractal image of the month - Discussion thread
« Reply #67 on: July 23, 2019, 10:36:02 AM »
In another thread some members suggested another kind of image contest, for example a theme-contest?
Well I'm very interested in your opinion about that. Would you participate?
#### Sabine62
• Fractal Freak
• Posts: 663
• It's just a jump to the left...
#### Re: Fractal image of the month - Discussion thread
« Reply #68 on: July 23, 2019, 11:16:18 AM »
My dear, IF I find the time I will ALWAYS participate I like these contests, not in it to win it, but because I love 'community'-thingies
And yes, themes, why not? We can try and will see if it works, right?
• Moderator
• Posts: 285
#### Re: Fractal image of the month - Discussion thread
« Reply #69 on: July 23, 2019, 11:29:44 AM »
I know you do
#### freakiebeat
• Fractal Fanatic
• Posts: 22
#### Re: Fractal image of the month - Discussion thread
« Reply #70 on: July 23, 2019, 05:33:04 PM »
What kind of themes would be considered?
Electricsheeper - www.esheeper.com
Freakie Beat Visuals - www.freakiebeat.com
• Moderator
• Posts: 285
#### Re: Fractal image of the month - Discussion thread
« Reply #71 on: July 23, 2019, 08:51:15 PM »
What comes to mind, and then we choose, together (all democratic Maybe a poll?
Let's make a list of themes, ideas and maybe it's possible. Why not?
• 3f
• Posts: 1481
#### Re: Fractal image of the month - Discussion thread
« Reply #72 on: July 24, 2019, 04:00:11 AM »
Theme selection via https://www.randomlists.com/random-words?dup=false&qty=1
The above link selects one random word, just now mine was "tiger".
but you can only take the first thing that comes up, not allowed to sit there and click until something you like shows up, yes it will make for some odd themes but will be a great challenge to artistic creativity, to capture the embodiment of a word in an image.
@Caleidoscope we will all have to trust you try that link and share what shows up just for a test. if it looks good maybe visit that link before the contest beginning announcement and include the word for the theme.
oh, this could be an off shoot in addition to the IMOTM contest and, in true fractal form, it becomes a contest between the contests, one will dominate and one will go to oblivion?
edit: or maybe both will survive
« Last Edit: July 24, 2019, 04:17:24 AM by 3DickUlus »
Fragmentarium is not a toy, it is a very versatile tool that can be used to make toys
https://en.wikibooks.org/wiki/Fractals/fragmentarium
• 3f
• Posts: 1481
#### Re: Fractal image of the month - Discussion thread
« Reply #73 on: July 24, 2019, 04:30:42 AM »
...
Maybe a message could be placed on the Home-page alerting users to the competition? Blinking? :}:}:}
I'd really love to see more participants, especially since we have members with such varied fractal interests
...
could send a note to all...
Please join the fun! Participate in the Image of the month contest!
...or
Don't forget to vote in the Image of the month contest!
• Moderator
• Posts: 285
#### Re: Fractal image of the month - Discussion thread
« Reply #74 on: July 24, 2019, 01:24:38 PM »
I tried the word generator but if you would do as you suggest you get a very difficult challenge. For example I've tried several times and this is what came up:
calm -chase -level -note - tall - hammer - field - glib - slap- abrasive - behave -ajar - roof - march -extra-large- serve -deafening -aware unkempt -children -cats -ring
I myself wouldn't know what to do with it
I've checked out the internet for more online generators, maybe you want to see what you think of it:
This one gives 3 randmom word, you could for example say that the challenge will be to use at least 2 words, it gives a bit more choise?
This one offers 2-3 them words:
http://www.boardgamizer.com/themes click on 'one other idea' and mostly they come up with something useful.
This one looks rather interesting too: it gives a 'Random Design Theme/Aesthetic Idea Generator'
for example: the theme will be: "combines soft abstract designs with a wing theme and uses warm, muted colors"
It offers one or two possible themes... You could ask which one they prefere.
https://www.springhole.net/writing_roleplaying_randomators/design-theme.htm
there are several kind of generators, quite nice.
or maybe this one:
https://www.magatsu.net/generators/art/index.php
It generates on topic.
I don't know if this is anything, but I understand correctly you could integrate it in your website. The advantage would be that is is verifiable. Maybe it is something, maybe not
html theme generator:
https://codepen.io/BreemClock/pen/yNbgGg
.................................................................................
I still think that involving the members is better. I don't want to be the one that comes up with a 'word' and most don't have a clue what to with it? I don't want to argue over a theme. I'm also not the most mathematical fraktalist on this forum, so it would be hard for me to be aware of all the possibilities. You are! Maybe you should pick the theme?
A poll would still be preferable to me. I (you) come up with say three themes (members can also put in theme ideas by mail, or note) And we let the members choose and most votes wins. Or another possibility is to let the winner, first price, determine the next challenge?
Also we have to make some rules, all fractal or a mix with multi media and fractal, backgrounds, etc.... ?
..........................................................
To have two contest... I don't mind... one regular one and one theme. We hold them at the same time. That's no problem and perhaps one has to go, and that is also not a problem
We do have to shorten the voting period for otherwise there is no time to decide the next challenge as. (and time to breath)
And I do like the message. And sending it once to alle members would be fine by me, ask them if they want to get the invitation monthly or not!
This is it for the moment, I do hope more will share their vision with us...? Input is ver welcome.
Have a great day, I am goïng into the field and enjoy the warm (hot) weather
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by quaz0r | 2020-02-18 09:06:46 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.43162792921066284, "perplexity": 4390.240365931464}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875143646.38/warc/CC-MAIN-20200218085715-20200218115715-00181.warc.gz"} |
https://search.r-project.org/CRAN/refmans/cvCovEst/html/adaptiveLassoEst.html | ### Description
adaptiveLassoEst() applied the adaptive LASSO to the entries of the sample covariance matrix. The thresholding function is inspired by the penalized regression introduced by Zou (2006). The thresholding function assigns a weight to each entry of the sample covariance matrix based on its initial value. This weight then determines the relative size of the penalty resulting in larger values being penalized less and reducing bias (Rothman et al. 2009).
### Usage
adaptiveLassoEst(dat, lambda, n)
### Arguments
dat A numeric data.frame, matrix, or similar object. lambda A non-negative numeric defining the amount of thresholding applied to each element of dat's sample covariance matrix. n A non-negative numeric defining the exponent of the adaptive weight applied to each element of dat's sample covariance matrix.
### Value
A matrix corresponding to the estimate of the covariance matrix.
### References
Rothman AJ, Levina E, Zhu J (2009). “Generalized Thresholding of Large Covariance Matrices.” Journal of the American Statistical Association, 104(485), 177-186. doi: 10.1198/jasa.2009.0101, https://doi.org/10.1198/jasa.2009.0101.
Zou H (2006). “The Adaptive Lasso and Its Oracle Properties.” Journal of the American Statistical Association, 101(476), 1418-1429. doi: 10.1198/016214506000000735, https://doi.org/10.1198/016214506000000735.
### Examples
adaptiveLassoEst(dat = mtcars, lambda = 0.9, n = 0.9)
[Package cvCovEst version 1.1.0 Index] | 2022-05-24 22:29:20 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7503959536552429, "perplexity": 2725.5993267539366}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662577259.70/warc/CC-MAIN-20220524203438-20220524233438-00270.warc.gz"} |
https://www.meritnation.com/ask-answer/question/the-passage-of-an-electric-current-through-a-conducting-solu/chemical-effects-of-electric-current/16251397 | # The passage of an electric current through a conducting solution results in bubbles of gases.?give reasons
Dear student
When electric current is passed through a conducting liquid solution , chemical reactions take place at each electrodes .The resulting effects are called chemical effects of current .The passage of an electric current through a conducting solution causes chemical reactions . As a result, bubbles of gas may be formed on the electrodes . Deposits of metal may be seen on the electrodes .These are the two chemical effects of electric current.
Regards
• 0
Hello
• 0 | 2021-01-24 03:39:22 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9370208382606506, "perplexity": 1072.2206546100588}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-04/segments/1610703544403.51/warc/CC-MAIN-20210124013637-20210124043637-00691.warc.gz"} |
https://www.nature.com/articles/s41598-021-01870-7?error=cookies_not_supported&code=291b1137-5da1-48f9-8933-4ab247cc6aa2 | ## Introduction
Rice fields are spatially monotonous1,2, yet they provide valuable habitats for several species, including aquatic plants, benthic invertebrates, and vertebrates1,3. They also provide essential alternative habitats for a wide range of species, including those in need of conservation, particularly due to the loss of natural habitats4,5. Rice production has greatly increased in recent years due to intensive practices for maximizing crop yield, but the habitat quality and biodiversity of rice fields have only decreased6,7,8,9,10. Intensive practices can be characterized by the excessive use of chemicals, such as herbicides and pesticides, expansion of farming areas, and the use of advanced machinery11. These intensive practices have been implemented worldwide and have severely decreased the wildlife biodiversity, such as birds, mammals, amphibians, and invertebrates12,13,14,15,16,17.
Rice fields can be structurally divided into paddy, levee, road, and ditch, with each component providing microhabitats with different ecological functions6,18,19,20. Of these habitats, paddies account for the largest area and can support higher species richness and abundance than the other microhabitat types21,22. This space can be used by various avian species depending on whether the paddy fields are flooded or dry, which varies according to the cultivation season21,22. The boundary between paddies is known as a levee, and it provides a necessary microhabitat that compensates for the decreased microhabitat function of the paddy when the density of rice is high during the growing season, which can prevent the access of some avian species18,23,24. Roads expand other microhabitats, such as levees and ditches, and form terrestrial ecosystems6,25. Ditches are paths that allow the irrigation of the paddy, forming aquatic ecosystems, and thus shaping the structures of the unique aquatic community, depending on the source of agricultural water, such as reservoirs and rivers6,25.
Pesticides and/or herbicides are intensively used in conventional rice fields, and it has been well-documented that they can directly kill avian species or indirectly reduce the abundance of food sources when used excessively22,26,27,28,29,30. Moreover, the effects of chemicals on habitat use vary among avian species31. In contrast, eco-friendly rice fields restrict or stop the use of pesticides and/or herbicides. Choi et al.32 reported that common greenshanks (Tringa nebularia) used eco-friendly paddies more than conventional paddies, while the habitat use of wood sandpipers (Tringa glareola) was not significantly affected by pesticide and/or herbicide use. Furthermore, some avian species such as grey herons (Ardea cinerea) used conventional rice fields more than eco-friendly rice fields33. However, previous studies have only evaluated the effects of chemicals on paddies at the species level, and no study has examined their effects on the microhabitat use (i.e., paddies, levees, ditches, and roads) of bird taxonomic groups (i.e., shorebirds, herons, waterfowl, and land birds).
The objective of this study was to evaluate the effects of chemical substance usage among intensive practices (i.e., eco-friendly vs. conventional) on different bird taxonomic groups using rice field microhabitats. We hypothesized that habitat use of shorebirds, herons, waterfowl and land birds are different according to microhabitat types (paddy, levees, ditches, and roads) in eco-friendly and conventional rice fields. In particular, we aimed to determine the (1) composition of the bird taxonomic groups using the rice fields and (2) differences in the microhabitat types used by the bird taxonomic groups in eco-friendly and conventional fields to broaden our understanding of the habitat structure and usage patterns of bird taxonomic groups in rice fields.
## Results
We observed a total of 64,736 individuals of 113 species, including 22 shorebird species (822 individuals), 11 heron species (9538 individuals), 15 waterfowl species (45,036 individuals), 53 land bird species (9116 individuals), and 12 other waterbird species, including cormorants, gulls, cranes, and watercock (224 individuals) (see Supplementary Table S1). The average number of individuals was the highest in October (6973 individuals) and the lowest in June (439.3 individuals). The average number of species was the highest in May (29.7 species) and the lowest in January (15 species) (Fig. 1).
### Pattern from the self-organizing map
The 36-month survey data were divided into four clusters using a self-organizing map based on the 113 bird species observed in the eco-friendly and conventional rice fields (Fig. 2). Cluster 1 appears to include only information from eco-friendly fields, in which shorebird richness and abundance were the highest (Figs. 3 and 4). The other three clusters are formed by a combination of both field types, but with cluster 2 dominated by herons, and clusters 3 and 4 by waterfowl (Fig. 4). These clusters were significantly different in the number of individuals and species (multi-response permutation procedure (MRPP), A = 0.14, P = 0.002). Land birds accounted for the largest proportion of individuals (28.95%) and species (43.96–63.80%) in cluster 1 and all clusters, respectively (Fig. 4). Among the waterbird taxonomic groups, shorebirds (29.54% and 34.07%), herons (67.33% and 36.99%), and waterfowl (95.46% and 31.68%) accounted for the largest proportions of individuals and species, respectively, in clusters 1, 2, and 3 (Fig. 4).
### Usage characteristics of eco-friendly and conventional rice fields
We found no spatial autocorrelation among the waterbirds, while land birds exhibited positive spatial autocorrelation (see Supplementary Figure S3). The generalized linear mixed model (GLMM) analysis showed that the relationship between habitat type and cultivation method varied between bird taxonomic groups (Table 1). Habitat type, cultivation method, and the interaction between habitat type and cultivation method were related to the distribution of shorebirds and herons. However, only habitat type was related to the distribution of waterfowl. The number of shorebirds and herons observed in eco-friendly rice fields was more than twice that of the observed in conventional rice fields (Fig. 5). Regardless of cultivation treatment, most shorebirds, herons, and waterfowl were observed in paddy fields, while most land birds were observed in ditches (Fig. 6). Generally, herons and waterfowl were more frequently observed in the eco-friendly than in the conventional rice fields, while more shorebirds were observed on the levees of the conventional rice field than on that of the eco-friendly fields. Land birds were observed in all microhabitats of the conventional rice fields, except levees (Fig. 6).
## Discussion
We identified differences in rice field use by bird taxonomic groups. The bird taxonomic groups had clearly different usage patterns and were differently affected by habitat type and cultivation method. Specifically, the microhabitat types (paddy, levee, ditch, and road) and management practice (eco-friendly and conventional field) provided unique habitat qualities that are used differently by bird taxonomic groups according to their habitat characteristics6,18,19,20. All bird taxonomic groups identified in this study used different microhabitat types, and each habitat fulfilled different functions for waterbirds and land birds. Furthermore, even for the same microhabitat type, the level of habitat use depended on the management practice.
Waterbirds, such as shorebirds, herons, and waterfowl, mostly used paddies, while land birds more frequently used ditches or roads. Paddies, which were heavily used by waterbirds, account for the largest area of rice fields and they change abruptly during the rice cultivation process21,22,24. This process affects the aquatic and terrestrial ecosystems, alternating them in the paddy fields21,22,24. Various food sources for waterbirds such as benthic organisms and spilled grains are repeatedly and periodically available, maintaining a frequent paddy use by waterbirds34,35,36.
Land birds used roads and ditches more than paddy fields. The narrow edge areas of roads and ditches have well-developed, diverse herbaceous plants, such as farm crops, reeds, and silver grass, which can be used for foraging or as resting spaces18,19, while the paddy is a space for growing rice, a single crop, and has a homogeneous vegetation structure18,19. It has been reported that higher biodiversity of herbaceous species, including crops, attracts more diverse taxa3, such as bird-feeding spiders, butterflies, and surface-roaming insects37,38. Therefore, land birds tend to use roads and ditches that offer a more diverse habitat3. In September, land birds were more abundant in the conventional fields than in the eco-friendly fields when the crops in the study areas matured (maximum counts, eco-friendly field = 97, conventional filed = 773; see Supplementary Table S2).
Eco-friendly cultivation paddies, which are used frequently by shorebirds, have a higher diversity of benthic organisms, a potential food source, than conventional cultivation paddies39,40. Even though these paddies had similar shapes as those of conventional fields, shorebirds used them considerably more because of the larger amount of available food. In contrast, shorebirds used levees in conventional cultivation fields more than levees in eco-friendly cultivation fields, which could be related to accessibility. In the area studied, the levees were managed in different ways according to the cultivation method. In eco-friendly fields, weeds were either left untouched or removed using a weeder, i.e., without complete removal, whereas herbicides were used in conventional fields, allowing for complete removal of weeds43. The levees in the conventional fields presented an open shape, in which shorebirds were more abundant, probably because they have a habit of foraging or resting in open environments41,42. Herons used the paddies, levees, and roads of the eco-friendly fields more than those of the conventional fields, because eco-friendly fields provided a higher abundance of potential food sources than the conventional fields39,44. Moreover, herons rarely used the ditch microhabitat because many of the ditches were concrete-lined, resulting in reduced food availability, which made them less attractive to herons than other microhabitats6,18,19. Waterfowl also used microhabitats of eco-friendly fields more than those of conventional fields, which could be because some paddies in the eco-friendly fields were watered, even after harvesting. Watered paddies are an important feeding ground for various waterfowl in winter45,46,47, where they were observed to be concentrated. Although land birds used all habitat types, they used conventional fields more than eco-friendly fields, a trend contrary to waterbirds. Certain farm crops grown in the conventionally cultivated rice fields at the study site (cultivated using pesticides) were not grown in the eco-friendly fields. These farm crops provided land birds with more diverse habitats in the conventional fields than in the eco-friendly fields and allowed them to forage or rest more38.
It has previously been found that rice cultivation techniques, such as pesticide and/or herbicide use and crop cultivation around paddies, could affect birds using rice fields22,27,41,45,48,49. The results of this study also support these findings, as it was found that waterbirds were more abundant in eco-friendly fields due to the larger amount of potential food21,30,33. It was also found that land birds were more abundant in fields that cultivated a higher number of plant crop species, which provided more diverse habitats, even if pesticides and/or herbicides were used. This increased habitat diversity was possible due to use of pesticides, which allowed various other farm crops to be grown. However, it does not mean that pesticide use is important. The various habitat structures created by the crops are important, and it would be better to have a variety of habitat structures without the use of pesticides.
In conclusion, this study reported that bird taxonomic groups in rice fields differ based on the agricultural techniques used, as they affect the habitat characteristics. As natural wetlands disappear, paddies provide alternative habitats for various birds. Rice paddies are artificial wetlands that can be changed more drastically through active human management over a short period of time than natural wetlands. Therefore, it is very important to understand the ecological characteristics and structure of paddy wetlands. The results of this study will be valuable for establishing management plans for several bird taxonomic groups that use rice fields. We concluded that (1) a combination of habitats and practice methods is considered for shorebirds and herons, (2) paddies are more important than any other habitat (e.g., levee, ditch, and road) for shorebirds and waterfowl, (3) herons use more diverse habitats than other waterbirds, (4) habitats and practice methods should be simultaneously considered for land birds, and (5) farm crops on the narrow edge areas of roads are important in rice fields. Consequently, seeking and implementing clear and systematic management plans for rice field habitats can contribute to the immediate protection and conservation of bird taxonomic groups.
The bird taxonomic groups are affected by a variety of factors such as soil management, water management, distance from breeding colonies and landscape structures between eco-friendly and conventional rice fields17,50. Therefore, future studies should focus on investigating the effects the management practices considering the other relevant factors. Moreover, further studies are also needed to confirm whether the effects of cultivation methods at the community level would also be valid at the species level.
## Materials and methods
### Study sites
This study was conducted in rice fields located in Nanjido-ri, Seokmun-myeon, Dangjin-gun, Chungcheongnam-do (37°02ʹN, 126°30ʹE: midwestern region of the Republic of Korea; Supplementary Figure S1). The rice fields were reclaimed in 1979, and developed by the Large-scale Comprehensive Agricultural Development Project, with a total area of 3904 ha. Rice was initially cultivated using conventional methods in the entire areas, but since 1999, eco-friendly cultivation methods have been used in some areas (574.2 ha). The eco-friendly and conventional rice fields are adjacent to one another, separated by roads, and irrigated by the same ditch51. The survey unit was the standardized field unit enclosed by levees and farm roads, measuring 0.45 ha ± 0.07 ha (mean ± SE). For this study, 446 eco-friendly rice fields and 442 conventional rice fields were selected.
The microhabitat types of rice fields were divided into paddies, levees, roads, and ditches. Cultivation activities (e.g., plowing, harrowing, and rice planting) are conducted throughout the season in this area, and some eco-friendly rice paddies are watered even after rice harvesting. Levees and roads are managed differently between eco-friendly and conventional rice fields. Generally, eco-friendly management includes both low-pesticide and organic farming; high pesticide use is defined as a feature of conventional farm management. Weeds on the levee and road of the eco-friendly rice fields were either left or physically removed using a weeder, while those on the conventional rice fields were removed using a chemical herbicide. In rice fields, roads were cultivated with farm crops along the narrow edge areas. Seventeen types of farm crops (e.g., soybeans, sesame, corn, leeks, perilla, napa cabbage, and spinach) were cultivated on conventional roads (Supplementary Figure S2). Farm crops were not grown in the eco-friendly levees or roads, even though some rice fields used pesticides. The period of the harvest of farm crops was mainly from September to October (Supplementary Table S2). The ditches consisted of concrete, but some, such as drainage ditches, consisted of soil in both the eco-friendly and conventional rice fields. Reeds (Phragmites australis) or silver grasses (Miscanthus sinensis) were grown in ditches composed of soil. Although some eco-friendly rice fields used pesticides (tiadinil), most did not (approximately 20 fields). Conventional rice fields used pesticides containing tiadinil, clothianidin, pyrazosulfuron-ethyl, or fentrazmide in all areas (Supplementary Table S3).
### Bird and habitat survey
Birds were surveyed once per month for 3 years from January 2014 to December 2016. The survey was conducted between 06:00 and 12:00 when visiting eco-friendly (446 fields) and conventional rice fields (442 fields), or along the road; all birds observed on the left and right sides were recorded, along with the field type they were found in. To minimize the misidentification of birds, the observation area was limited to one field (approximately 100 m in length) adjacent to the road. A total of 888 fields were observed per month.
Birds that were flying or sitting on utility poles or wires were excluded from the record, but raptors and swallows (Hirundo rustica) were recorded, even if they were flying. The recorded birds were divided into waterbirds and land birds based on field observations and habitat use obtained from previous studies18. Waterbirds were further subdivided into shorebirds, herons, and waterfowl. The habitat type of the flying swallows was recorded as paddy. For raptors, the habitat used for food acquisition or resting was recorded as the habitat type. To minimize bias due to weather, the survey was not conducted on rainy or snowy days.
### Statistical analysis
This study used a self-organizing map, which is an artificial neural network using unsupervised learning, to identify the characteristics of bird taxonomic groups observed for 3 years from 2014 to 201652. Self-organizing maps are effective for exploratory data analysis53. In particular, they are widely used to understand the distribution or structure of animal assemblages and are suitable for data classification, patternization, and visualization54. They are robust, even in the presence of outliers, and their results are easy to understand and interpret55. Self-organizing maps are computed through an adaptive learning process that removes noise from the dataset56. They are connected in the direction from the input layer to the output layer, and the results of neurons in the output layer have a connection strength that is updated by unsupervised learning. The neurons in the output layer have “winner-takes-all” structures, and neurons with higher similarity to the connection strength are arranged closer to the output neurons on a two-dimensional hexagonal grid57.
The data (number of individuals: 113 species × 2 cultivation methods × 36 surveys) were assigned to the input layer of the self-organizing map after log-transformation (log(1 + number of individuals)) due to the differences in the number of individuals of each species. The number of output layer neurons was determined by the heuristic rule of 5 $$\sqrt{n}$$, as suggested by Vesanto et al.58, where n is the number of data points in the input layer (72 surveys). The final model generated 42 output neurons (six horizontal and seven vertical). After the self-learning of the self-organizing map, neurons were classified into groups based on the similarity of each neuron. The distance between neurons was measured by the Euclidean distance, and groups were classified using the Ward linkage method54. An MRPP was used to evaluate significant differences between groups.
A generalized linear mixed model (GLMM, Poisson distribution, and log link) was used to evaluate the effects of microhabitat type (i.e., paddy, levee, ditch, and road) and cultivation method (eco-friendly and conventional) on the number of birds per taxonomic group. Spatial autocorrelation analysis was conducted to examine the spatial characteristics of the data before applying the GLMM at a fine spatial scale (field scale). We tested the spatial autocorrelation using Moran’s I statistics59. When the result of the spatial autocorrelation analysis was significant, GLMM analysis was conducted by applying spatial autocorrelation. In the GLMM, the number of birds per taxonomic group was designated as a response variable, and the habitat type and cultivation method were considered as fixed effects. The timing of the survey and the location of each field were treated as random effects.
All analyses were performed using R statistical software V 3.6.160. The “kohonen”61, “vegan”62, “lme4”63, and “spaMM” packages64 were used for the self-organizing map analysis, MRPP, GLMM without autocorrelation, and GLMM with autocorrelation, respectively. | 2022-12-04 03:28:27 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3915601968765259, "perplexity": 6079.173517848946}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710953.78/warc/CC-MAIN-20221204004054-20221204034054-00014.warc.gz"} |
https://www.khanacademy.org/math/calculus-home/derivative-applications-calc/lhopitals-rule-calc/a/lhopitals-rule-review | # L'Hôpital's rule review
L'Hôpital's rule helps us find many limits where direct substitution ends with the indeterminate forms 0/0 or ∞/∞. Review how (and when) it's applied.
## What is L'Hôpital's rule?
L'Hôpital's rule helps us evaluate indeterminate limits of the form start fraction, 0, divided by, 0, end fraction or start fraction, infinity, divided by, infinity, end fraction.
In other words, it helps us find $\displaystyle\lim_{x\to c}\dfrac{u(x)}{v(x)}$, where $\displaystyle\lim_{x\to c}u(x)=\lim_{x\to c}v(x)=0$ (or, alternatively, where both limits are plus minus, infinity).
The rule essentially says that if the limit $\displaystyle\lim_{x\to c}\dfrac{u'(x)}{v'(x)}$ exists, then the two limits are equal:
$\displaystyle\lim_{x\to c}\dfrac{u(x)}{v(x)}=\displaystyle\lim_{x\to c}\dfrac{u'(x)}{v'(x)}$
## Using L'Hôpital's rule to find limits of quotients
Let's find, for example, $\displaystyle\lim_{x\to 0}\dfrac{7x-\sin(x)}{x^2+\sin(3x)}$.
Substituting x, equals, 0 into start fraction, 7, x, minus, sine, left parenthesis, x, right parenthesis, divided by, x, start superscript, 2, end superscript, plus, sine, left parenthesis, 3, x, right parenthesis, end fraction results in the indeterminate form start fraction, 0, divided by, 0, end fraction. So let's use L’Hôpital’s rule.
\begin{aligned} &\phantom{=}\displaystyle\lim_{x\to 0}\dfrac{7x-\sin(x)}{x^2+\sin(3x)} \\\\ &=\displaystyle\lim_{x\to 0}\dfrac{\dfrac{d}{dx}[7x-\sin(x)]}{\dfrac{d}{dx}[x^2+\sin(3x)]}\qquad\gray{\text{L'Hopital's rule}} \\\\ &=\displaystyle\lim_{x\to 0}\dfrac{7-\cos(x)}{2x+3\cos(3x)} \\\\ &=\dfrac{7-\cos(0)}{2(0)+3\cos(3\cdot0)}\qquad\gray{\text{Substitution}} \\\\ &=2 \end{aligned}
Note that we were only able to use L’Hôpital’s rule because the limit $\displaystyle\lim_{x\to 0}\dfrac{\dfrac{d}{dx}[7x-\sin(x)]}{\dfrac{d}{dx}[x^2+\sin(3x)]}$ actually exists.
Problem 1.1
$\displaystyle\lim_{x\to 0}\dfrac{e^x-1}{2x}=?$
Want to try more problems like this? Check out this exercise.
## Using L'Hôpital's rule to find limits of exponents
Let's find, for example, $\displaystyle\lim_{x\to 0}(1+2x)^{^{\LARGE\frac{1}{\sin(x)}}}$. Substituting x, equals, 0 into the expression results in the indeterminate form 1, start superscript, start superscript, infinity, end superscript, end superscript.
To make the expression easier to analyze, let's take its natural log (this is a common trick when dealing with composite exponential functions). In other words, letting y, equals, left parenthesis, 1, plus, 2, x, right parenthesis, start superscript, start superscript, start fraction, 1, divided by, sine, left parenthesis, x, right parenthesis, end fraction, end superscript, end superscript, we will find $\displaystyle\lim_{x\to 0}\ln(y)$. Once we find it, we will be able to find $\displaystyle\lim_{x\to 0}y$.
natural log, left parenthesis, y, right parenthesis, equals, start fraction, natural log, left parenthesis, 1, plus, 2, x, right parenthesis, divided by, sine, left parenthesis, x, right parenthesis, end fraction
\begin{aligned} \ln(y)&=\ln\left((1+2x){^{\LARGE\frac{1}{\sin(x)}}}\right) \\\\ &=\dfrac{1}{\sin(x)}\ln(1+2x)\qquad\gray{\text{Logarithm properties}} \\\\ &=\dfrac{\ln(1+2x)}{\sin(x)} \end{aligned}
Substituting x, equals, 0 into start fraction, natural log, left parenthesis, 1, plus, 2, x, right parenthesis, divided by, sine, left parenthesis, x, right parenthesis, end fraction results in the indeterminate form start fraction, 0, divided by, 0, end fraction, so now it's L’Hôpital’s rule's turn to help us with our quest!
\begin{aligned} &\phantom{=}\displaystyle\lim_{x\to 0}\ln(y) \\\\ &=\displaystyle\lim_{x\to 0}\dfrac{\ln(1+2x)}{\sin(x)} \\\\ &=\displaystyle\lim_{x\to 0}\dfrac{\dfrac{d}{dx}[\ln(1+2x)]}{\dfrac{d}{dx}[\sin(x)]}\qquad\gray{\text{L'Hopital's rule}} \\\\ &=\displaystyle\lim_{x\to 0}\dfrac{\left(\dfrac{2}{1+2x}\right)}{\cos(x)} \\\\ &=\dfrac{\left(\dfrac{2}{1}\right)}{1}\qquad\gray{\text{Substitution}} \\\\ &=2 \end{aligned}
We found that $\displaystyle\lim_{x\to 0}\ln(y)=2$, which means $\displaystyle\lim_{x\to 0}y=e^2$.
Since natural log, left parenthesis, x, right parenthesis is continuous, we know that $\displaystyle\lim_{x\to 0}\ln(y)=\ln\left(\lim_{x\to 0}y\right)$, which means $\ln\left(\displaystyle\lim_{x\to 0}y\right)=2$:
\begin{aligned} \ln\left(\displaystyle\lim_{x\to 0}y\right)&=2 \\\\ e^{\ln\left(\displaystyle\lim_{x\to 0}y\right)}&=e^2\qquad\gray{\text{Raise }e\text{ by both sides}} \\\\ \displaystyle\lim_{x\to 0}y&=e^2 \end{aligned}
Problem 2.1
$\displaystyle\displaystyle\lim_{x\to0} [\cos\left(2\pi x \right)]^{^{\LARGE\frac 1 x}}=?$ | 2017-10-22 17:17:34 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 39, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 12, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8136734366416931, "perplexity": 7531.073994878986}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187825399.73/warc/CC-MAIN-20171022165927-20171022185927-00124.warc.gz"} |
https://forum.azimuthproject.org/discussion/1336/categorical-foundations-of-network-theory | Howdy, Stranger!
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Categorical foundations of network theory
Some good news! Jacob Biamonte applied for and received a grant from the Foundational Questions Institute (FQXi) to have a small meeting for about 4 nights in Torino, Italy — at the ISI Foundation, where he works. The meeting will focus on the mathematical and conceptual foundations of network theory. The ISI Foundation has many researchers who work on traditional aspects of complex networks, so this is a pretty good location for it.
He invited Tobias Fritz, Eugene Lerman and David Spivak and me to speak, and it looks like most of us will be able to make it. We need to choose a time in the window from April 15 to June 1, 2015.
We should decide on what to do. Besides discussing and putting together our different ideas on network theory — the most important part — it might be good to have our talks videotaped and put on the web. Since our talks will be open to the public, maybe some other Azimuth members can show up.
Any other good ideas?
Each funded grant is required to deliver a 'product' and also to have a 'statement'. These, as taken from the application, are below.
Product: Network theory is a diverse subject which developed independently in several disciplines to rely on graphs with additional mathematical structure to model everything from complex systems to toy physical theories. The sessions will be aimed to further our understanding and also raise interest in the mathematical theory underlying the relations between seemingly different networked systems. We have a professionally maintained laboratory webpage (www.TheQuantumNetwork.org). We will deliver the following: (i) an event webpage for the sessions will be created; after the work sessions the webpage will contain (ii) slides of all talks; (iii) abstracts of all talks; and (iv) a list of attendees.
Statement: The intensive work sessions will enable FQXi members to meet with several other researchers and hence build leverage in an emerging and foundational field. Mathematical network theory explores the interplay and pinpoints the relationships between the use of networks ranging from e.g. ecological networks, tensor networks in quantum physics to even quantum constructor theory as a formal network theory. The sessions will be advertised and open to the public, and the invited speakers and local attendees should attract several researchers. It would otherwise not be possible using our existing resources.
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RE: putting the talks on youtube... It's in the works. I planned fully to aim for this. I'm pretty sure I can pull this off. We just need to find a good quality camera as we already have someone who knows how to edit. It's great stuff and thanks a ton John.
Comment Source:RE: putting the talks on youtube... It's in the works. I planned fully to aim for this. I'm pretty sure I can pull this off. We just need to find a good quality camera as we already have someone who knows how to edit. It's great stuff and thanks a ton John.
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2.
edited May 2014
RE: putting the talks on youtube… It’s in the works.
Great!
One thing that's on my mind is the gap between the "academic" and "nonacademic" sides of the Azimuth Project. It's attracting academics who publish papers and run conferences... and nonacademics who program, blog and do research for the sheer love of it. It would be nice if there were more synergy between the two. I've been putting a lot of work into building up the academic side since, being an academic myself, I know my energy for Azimuth will falter if I don't make it part of my work. But I really like how it attracts nonacademics and I wish projects like this conference offered more for them too. They can attend... if they can get there. They can watch videos of the talks - that's great. But maybe there's more we can do to integrate the academics and nonacademics - not just for this conference, but in general.
Comment Source:> RE: putting the talks on youtube… It’s in the works. Great! One thing that's on my mind is the gap between the "academic" and "nonacademic" sides of the Azimuth Project. It's attracting academics who publish papers and run conferences... and nonacademics who program, blog and do research for the sheer love of it. It would be nice if there were more synergy between the two. I've been putting a lot of work into building up the academic side since, being an academic myself, I know my energy for Azimuth will falter if I don't make it part of my work. But I really like how it attracts nonacademics and I wish projects like this conference offered more for them too. They can attend... if they can get there. They can watch videos of the talks - that's great. But maybe there's more we can do to integrate the academics and nonacademics - not just for this conference, but in general.
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3.
But maybe there’s more we can do to integrate the academics and nonacademics - not just for this conference, but in general.
Yes, that would be good. I think that the Azimuth coding projects offer a lot to talented coders who work in industry and elsewhere. At ISI, I think they do have some industrial partnerships for some of the groups (smart cities using sensors I think). I can talk to them and see what interests they have in this event. Also, it might be neat to hear from a few professionals quickly, relating to how they use network theory in industry.
Comment Source:> But maybe there’s more we can do to integrate the academics and nonacademics - not just for this conference, but in general. Yes, that would be good. I think that the Azimuth coding projects offer a lot to talented coders who work in industry and elsewhere. At ISI, I think they do have some industrial partnerships for some of the groups (smart cities using sensors I think). I can talk to them and see what interests they have in this event. Also, it might be neat to hear from a few professionals quickly, relating to how they use network theory in industry. | 2020-07-12 18:16:52 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2096671462059021, "perplexity": 1181.116541236397}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-29/segments/1593657139167.74/warc/CC-MAIN-20200712175843-20200712205843-00286.warc.gz"} |
http://www.ni.com/documentation/en/labview-comms/2.0/m-ref/sortrows/ | From 12:00 PM - 8:00 PM CST on Thursday, October 18, ni.com will be undergoing system upgrades that may result in temporary service interruption.
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sortrows
Version:
Sorts the rows of a matrix.
Syntax
c = sortrows(a)
c = sortrows(a, b)
[c, d] = sortrows(a)
[c, d] = sortrows(a, b)
a
Matrix with the rows to be sorted.
b
Columns of a for sorting the rows. b is a vector of integral numbers.
c
Sorted rows of a. Sorts the rows of a in ascending order if elements of b are positive. Sorts the rows of a in descending order if elements of b are negative. MathScript sorts complex vectors by magnitude and angle, in that order. c is a matrix of the same size as a.
d
Row indexes in a of the rows in c. d is a vector of integral numbers. The output data type is double precision floating-point number.
A = [6, 2, 3, 4; 4, 3, 2, 1];
[C, D] = sortrows(A, [1, 2])
Where This Node Can Run:
Desktop OS: Windows
FPGA: Not supported | 2018-10-18 22:50:11 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.24848951399326324, "perplexity": 2106.8109940988766}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-43/segments/1539583512015.74/warc/CC-MAIN-20181018214747-20181019000247-00198.warc.gz"} |
http://neeanders.de/caso4-acid-or-base.html | ## Caso4 Acid Or Base
KOH We know that a neutralization reaction is as follows: "acid + base" \ -> \ "salt + water" Here, we got: HBr+KOH->KBr+H_2O Usually, we use the Bronsted-Lowry acid-base theory, but here, we cannot use it, as we do not know which substance donated the hydrogen ion or which substance received it. K2SO 4, Na 2 SO 4, CaSO4, MgSO 4 and CuSO 4 can be obtanied by sulphuric acid. (Example: BaCO 3) Weak Electrolytes : Molecular compounds that partially dissociate, which are primarily weak acids and bases. (c) Oxidation-Reduction: Ca(s) has an oxidation number of 0, while Ca2+(aq) has an oxidation number of +2—hence Ca is being oxidized. 900 seconds. Start your trial now! First week only $4. Chapter 19 "Acids, Bases, and Salts". Nitric acid (HNO3) ( H N O 3) is one of the 7 known acids that are recognized as strong acids. During a titration the following data were collected. These short objective type questions with answers are very important for Board exams as well as competitive exams. When a base accepts a proton its conjugate acid is formed [e. 2H2O Uses:-1. Upvote (0). The colour of neutral litmus solution is. 0M) Safety Data Sheet according to Federal Register / Vol. Question 5. H2SO4 is a colorless viscous liquid at room temperature. Which of the following chemical reactions represents an acid-base reaction? a. The phosphate ion and K ion merely "swapped" charges. The hypotheses were that administration of oral Ca as CaCl2 and CaSO4 maintains blood total Ca (tCa) concentrations. heat 75 mL of 0. This is due to the neutralization reaction that converts acid into water and salt. base copper hydroxide Cu (OH)2. Mixing an acid with substances that are bases are examples of neutralization reactions. Neutralization can be backed up by acid and base theories. RTECSNumber : WS6920000. Acid + base --> salt + water. Use stoichiometry to relate the data from an acid-base titration to the amount of a metal ion removed by a cation-exchange column. 👎Not Helpful. Neutralization. All forms are white solids that are poorly soluble in water. Transcribed Image Textfrom this Question. The experimental results are pre- HCl (3 and 6) mol‚dm-3 + CaCl2 solutions was obtained sented in Table 10 and graphically in Figure 11. [Note: Pure compound is a solid below 51°F. Use this page to learn how to convert between grams CaSO4. So, it exists as an aqueous solution. There are virtually no molecules of a strong acid or base in solution, only ions. LIST IONIC. 2 2 3 2 2NaOH + CO Na CO + H O A base which is soluble in water is called an alkali. , HCl(aq), H 2 SO 4 (aq), HClO 4 (aq); NaOH(aq)]. 2 Brønsted-Lowry Acids and Bases LEARNING GOAL Identify conjugate acid-base pairs for Brønsted-Lowry acids and bases. Find the similar compound on the other side of the reaction. Acid-Base Reaction. The three most common indicators to test for acids and bases are CaSO4. This is due to the neutralization reaction that converts acid into water and salt. Neutralization reactions can make salts along with some other products. The neutral reaction between a strong and weak acid brings forth an acidic salt. Start studying Topic 8 Acid and Bases. (a) Plaster of Paris is written as CaSO4. Acid + Base Complex ion H + H + • •O 2 • • H H + H O H Example The acid-base bond is a coordinate covalent bond. base: anything that accepts a [H+] (proton acceptor) acid + base <=> acid + base HNO 2 + H 2 O <=> NO 2-+ H 3 O + The Trick- Pick a compound on the left side of the equation. A solution is prepared by dissolving 10. Clear All strong acid Ba(C1O4)2 weak acid HC104 strong base CH3COOH weak base Ca(OH)2 soluble salt AgaCO3 insoluble salt Classify each of the following substances as either a strong or weak acid, strong or weak base, or a soluble or insoluble salt. This reaction is similar to the neutralization reaction between acid and a base to form salt and water. A strong base is a base that ionizes completely in a solution of water and gives -OH ions and a weak base is a base that ionizes completely in a solution of water. National …. Now you must be clear about the concept of these reaction. Tap again to see term 👆. When a base and an acid react together, AKA neutralization reaction, it forms water, or H2O,which is neither a base or an acid. SO 4 2-is all in all a very weak base, so Al 3+ is easily a stronger acid and wins this battle, so. CaSO4 IUPAC Name: calcium sulfate Type of Substance Composition: mono-constituent substance Sulfuric acid, calcium salt Sulfuric acid, calcium salt (1:1) Sulphate, Calcium legante a base gesso nawóz phosphogypse phosphogypsum produkt uboczny z instalacji mokrego odsiarczania spalin. molecular weight of CaSO4. Solution: A reaction in which an acid and a base react with each other to give a salt and water is termed as a neutralization reaction. com ️📚👉 Get Notes Here: https://www. Chapter 19 "Acids, Bases, and Salts". 7 mL initial reading of acid = 60. To prepare a solution from a solid reagent, please use the Mass Molarity Calculator. The Neutralization in other container It will be observed that the marble tile on which Calcium Hydroxide was added after pouring Sulphuric Acid remains unharmed. The chemistry of acids and bases, and details of acid-base titration analysis were covered in Experiment 18. Jul 14, 2020 · Look at the reaction below. Blue litmus becomes dry in presence of dry HCl gas. NaCl, CaSO4 Acidic Salts : Strong Acid + weak base pH value is less than 7 eq. Solution: A reaction in which an acid and a base react with each other to give a salt and water is termed as a neutralization reaction. Neutralization reactions can make salts along with some other products. For example, if a hydrogen atom, which consists of one proton and one. I'll tell you the Acid or Base list below. In this reaction, energy is evolved in the form of heat and thus, such reactions are. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. Need explanation for: A parallel-plate capacitor of area A, plate separation d and capacitance C is filled wih four dielectric materials having dielectric constants k1, k2, k3. K2SO 4, Na 2 SO 4, CaSO4, MgSO 4 and CuSO 4 can be obtanied by sulphuric acid. To learn about the sodium sulfate, subscribe BYJU’S – The Learning App!. Given total component composition and pHinitial, calculate the acid or base to change the solution to a second pH, pHfinal (initially 8. c) Acids are compounds of hydrogen cations with an acidic residue: HNO3 - nitric acid; H2SO4 - sulfate acid; H3PO4 - phosphoric acid. This is a constant that measures the amount of acidic or basic ions in a solution. What acid and base would you use to form caso4? The calcium carbonate base and sulfuric acid can form calcium sulfate salt. H 2 SO 4 + CaCl 2 CaSO4 + HCl d. 12H2O,because in this compound, 2 water molecules are attached to one calcium sulphate molecule. Its melting point is 10 ̊C (50 ̊F), boiling point 337 ̊C (638. KOH We know that a neutralization reaction is as follows: "acid + base" \ -> \ "salt + water" Here, we got: HBr+KOH->KBr+H_2O Usually, we use the Bronsted-Lowry acid-base theory, but here, we cannot use it, as we do not know which substance donated the hydrogen ion or which substance received it. What volume of concentrated nitric acid (15. Acids and Bases • Alkanes • Alkenes • Atomic History • Atomic Structure • Bonding • Calorimetry • Density • Electromagnetic Radiation • Equilibrium • Gases • Gas Laws • Kinetics • Nomenclature • Measurement • The Mole • Oxidation-Reduction • Periodic Table • Polarity • Radioactivity • Reactions. 7 4 × 1 0 − 5. The hypotheses were that administration of oral Ca as CaCl2 and CaSO4 maintains blood total Ca (tCa) concentrations. Describe the effect of pH on the solubility of a particular molecule. Due to the common ion effect, if the concentration of sulfate increases, it will affect the Ksp equilibrium of CaSO4. READ: What material works best on a windmill blade? Is calcium chloride acidic or basic? CaCl2 is a salt of strong acid HCl and strong base Ca(OH)2. Unfortunately calcium sulphate, gypsum,$\ce{CaSO4}\$, is depressingly stable and nothing non-deadly will dissolve it. Classify Each Of These As An Acid Or A Base. H2Co3 \rightarrow H2O + CO2 \\ B. The weak acids include most all acids, and the weak bases include all the non-hydroxide bases. The reaction to form acetic acid is used in certain silicone caulks, leading to the familiar smell of vinegar (vinegar is a 5% solution of acetic acid in water) while the caulk cures. Now, sulfuric acid is a strong acid but NH4OH is a weak base. One of them contains distilled water and the. 001 M, calculate the acid to lower the solution pH to 6. I'll tell you the Acid or Base or Neutral list below. Which reaction is an example of an acid base neutralization reaction? {eq}A. acid sulphuric acid H2SO4. Sulfuric Acid - H 2 SO 4 H2So4 [So2(Oh)2] [S(Oh)2O2] Battery Acid Sulphuric Acid Oil Of Vitriol Hydrogen Sulfate H2SO4 Molar Mass H2SO4 Oxidation Number Potassium Hydroxide - KOH. 3BrO-(ag) → BrO3 -(ag)+2Br-(ag) A plot of 1/[BrO-] vs. Aqueous solutions of acids have a sour taste. ZnCl 2 + MgSO4 ZnSO 4 + MgCl 2 c. Brønsted in Denmark and T. Calcium Acetate Powder, Lab Grade. Calculate the concentration of acetate ion in the solution and its p H. National Center for Biotechnology Information. Acids, Bases and Salts All substances are acidic, neutral or basic (alkaline). In 1923, J. The product is a complex or complex ion. Is caco3 an acid or base? calcium carbonate is a salt, it is neither acid nor base. (b) Both A and R are true but R is not the correct explanation of A. asked • 05/28/19 Ca(OH)2+H2SO4=>CaSO4+H2O. These short solved questions or quizzes are provided by Gkseries. Therefore the solution will be basic. Amphoprotic and amphiprotic. There are four different neutralization reactions: 1. Answers: 2 Get Other questions on the subject: Chemistry. 7H20 is actually a hydrated chemical compound of normal CaSO4 or calcium sulfate. I think Mg+ is a base and so4 is an acid. How will you test the presence of this gas? Why do we pass hydrogen gas through soap solution why can't we burn it near the mouth of test tube and check it out by pop sound; What is the percentage of urea in detergents? Difference between weak base and. Which lists the steps in the correct order of occurrence? A: i, ii, iii, iv B: ii, iii, iv, i C: iii, ii, i, iv D: iv, iii, ii, i. (b) Acid-Base reaction: There is no change in oxidation number for any of the elements in this reaction—hence it is NOT an oxidation- reduction reaction. Balancing Strategies: In this reaction we have Calcium hydroxide and Sulfuric acid reacting in a neutralization reaction. Strong Base Anion Resin. Perchloric acid is a chlorine oxoacid. (Daily Double) 0. Therefore, you can see, white precipitate is dissolved and colorless solution is formed with time. A) Ca(NO3)2(aq) + Li2SO4(aq) - CaSO4(s. All forms are white solids that are poorly soluble in water. Class 10 Science Chapter 2 Important Questions are given below for the practice of Acids, Bases and Salts based questions for session 2021-22. 2 Ca2+ and SO42-for solution 2 are less than for solution 1 because the ionic strength of solution 2 is greater than the ionic strength of solution 1, and as a result [Ca2+] and [SO 4 2-] must be larger in solution 2 for both solutions to satisfy the K sp expression. 25 mL, find the final volume reading of the base. ; Colorless to dark-brown, oily, odorless liquid. < 7) and Yis a base (pH =10, i. Which of the following chemical reactions will this be Li + CaCl LiCl + Ca?. Acid + base --> salt + water Example: H2SO4 + …. Example 3a(b) amount of acid or base to change pH. All three beakers originally contained a suspension of brownish purple Cr(OH) 3 (s) (center). Chemistry, 22. Transcribed image text: Part A Identify H2SO4 (aq) as an acid or a base. Dissolved in water, the pH will be slightly higher than 7, which is basic. Stronger acids, for example sulfuric or phosphoric acid, have larger dissociation constants; weaker acids, like acetic acid, have smaller dissociation constants. What are the end products of a neutralization reaction? a) Gas, Salt b) Salt, water c) Water, Base d) Base, Salt Explanation Acids react with bases to give salt and water. d) Salts are metal compounds with an acidic residue: KNO3 - potassium nitrate; CaSO4 - calcium sulfate; K3PO4 - potassium orthophosphate; FeCl2 - ferric chloride. Jan 09, 2018 · 13. Calculate the degree of dissociation of acetic acid in its 0. acid sulphuric acid H2SO4. Safety and Handling. This increases the amount of hydroxide ion in the solution produced in the reaction and renders it slightly basic. The following reaction shows the products when sulfuric acid and aluminum hydroxide react. ) H+ + OH- = H2O. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. Know the strong acids and bases on the accompanying hand-out "Strong and Weak Acids and Bases". d) CaSO4 <---> Ca2+ + SO42-; If sulfuric acid is added, the concentration of sulfate will increase proportionally. That is also the reason why it precipitates out in the solution. All forms are white solids that are poorly soluble in water. ZnCl 2 + MgSO4 ZnSO 4 + MgCl 2 c. List molecules Acid and Base. It is an industrial alcohol and not for consumption. The other product of a simple neutralization is a salt. Non-metal oxide acidity is defined in terms of the acidic solutions formed in reactions with water—for example, sulfur …. Therefore the solution will be basic. H2SO4 + Ca(OH)2 \rightarrow CaSO4 + 2H2O \\ C. The reaction quotient, Q, will be greater in magnitude than K and the equilibrium will shift towards the reactants. acid base Subr Previous Answers Correct Part B Write a chemical equation showing how this is an acid according to the Arrhenius definition. 100 L The dissoci. READ: What material works best on a windmill blade? Is calcium chloride acidic or basic? CaCl2 is a salt of strong acid HCl and strong base Ca(OH)2. No change in color in phenolphthalein. (a) X is a base and Y is an acid (b) Both X and Y are acidic solutions (c) X is an acid and Yis a base (d) Both X and Y are bases Answer: (c) Any solution having pH > 7 will be a base while the solution having pH < 7 will surely be an acid. Baking Soda (NaHCO3) is a weak base. Identify all of the phases in your answer. Note that rounding errors may occur, so always check the results. I'll tell you the ionic or Molecular bond list below. mL of the base were required to neutralize the sample. B) H2SO4 (aq) + Ca (OH) 2 (aq) → CaSO4 (aq) + 2 H2O (l) Explanation: A is a reaction between a salt FeCl3 and a base KOH C is a n acid decomposing on it's own to form two products D is mercury, a metal reacting with oxygen. Acids and Bases. State three examples each of acids, bases, and salts commonly used in therapeutic processes. There are virtually no molecules of a strong acid or base in solution, only ions. Harmful to aquatic life with long lasting effects. CaSO4 is neather acid or base it is a salt which means it isnutreal. In this reaction, energy is evolved in the form of heat and thus, such reactions are. Example 3a(b) amount of acid or base to change pH. May 28, 2019 · Chemistry Stoichiometry Acid Base Reaction. Compounds - Acid, Base or Salt? Learn with flashcards, games, and more — for free. and to the non-metal anion, we add appropriate units of #H^+# to give the parent acid, i. (c) A is true but R … Continue reading Assertion and Reason Questions for Class 10 Science Chapter 2 Acids, Bases. View transcribed image text. Sodium sulfide (Na2S) is an strong alkaline solution and is acidic in nature. What is the conjugate base of HSO4-? SO42- H2SO4 SO3 H2O I II III IV. Answer and Explanation: 1 Become a Study. TABLE OF CONJUGATE ACID-BASE PAIRS Acid Base K a (25 oC) HClO 4 ClO 4 - H 2 SO 4 HSO 4 - HCl Cl- HNO 3 NO 3 - H 3 O + H 2 O H 2 CrO 4 HCrO 4 - 1. What volume of concentrated nitric acid (15. NaNO 2 - basic (NO 2-is a weak base - the conjugate base of a weak acid,HNO 2) NO 2-+ H2 O X HNO 2 + OH-NH 4 Cl - acidic (NH 4 + is a weak acid - the conjugate acid of a weak base, NH 3) NH 4 + + H 2 O X H 3 O + + NH 3 Li 2 SO 4 - basic (SO 4 2-is a weak base - the conjugate base of a weak acid,HSO 4. 25 mL, find the final volume reading of the base. Neutralization is the act of making an acidic or basic substance chemically neutral, meaning a pH of 7. Acid + Base Complex ion H + H + • •O 2 • • H H + H O H Example The acid-base bond is a coordinate covalent bond. Use stoichiometry to relate the data from a complexometric titration to the amount of metal ion in a solution. 8 x 10–1 H 2 C 2 O 4 (oxalic acid) HC 2 O 4 – 5. Conjugate acids and bases: When an acid loses a proton, its product is called the conjugate base of that acid. HOW STRONG ARE ACID OR BASE SOLUTIONS?A pH scale is a measure of how acidic or basic a substance is. NH 4 OH + KCl KOH + NH 4 Cl ____ 12. In 1923, J. MgSo4 is Acid. Open Visual Minteq software, everything is initialized; 2. Given total component composition and pHinitial, calculate the acid or base to change the solution to a second pH, pHfinal (initially 8. ; Colorless to dark-brown, oily, odorless liquid. Which of the following chemical reactions represents an acid-base reaction? a. Sodium carbonate is a basic salt because it is a salt of (a) strong acid and strong base (b) weak acid and weak base (c) strong acid and weak base (d) weak acid and strong base. Best Answer. 5 L saturated solution of CaSO4, does the concentration of Ca 2+ increase, decrease, or stay the same? Justify your answer. Video $$\PageIndex{1}$$: Chromium(III) Hydroxide [Cr(OH) 3 or Cr 2 O 3 •3H 2 O] is an Example of an Amphoteric Oxide. Nitric acid (a strong acid) Nitrous acid (a weak acid). For more questions, visit to discussion forum and ask your doubts. Is na2co3 an acid salt? NaHCO3 is a mild acid salt, H2CO3, and a solid base, NaOH. How do you know if a salt is soluble in water or not? Memorize the rules or …. Ex: Zn + HCl = ZnCl2 + H2. CaSO4 (used in plaster of Paris) Salt compound. This is a constant that measures the amount of acidic or basic ions in a solution. Now let’s move further with acid base reactions or neutralization reaction. compounds derived from the reaction of a strong base with a weak acid or a strong acid with a weak base or a solution of a weak base and one of its salts. Devices to remove gases like SO3 from smoke stacks. 80 M H2SO4 average volume of acid used =2. These short solved questions or quizzes are provided by Gkseries. 90 x 10-2 [H 2 SO 3] = SO 2 (aq) + H2 O HSO. 12H2O,because in this compound, 2 water molecules are attached to one calcium sulphate molecule. A strong base is a base that ionizes completely in a solution of water and gives -OH ions and a weak base is a base that ionizes completely in a solution of water. Only in a strong acid + strong base titration will the equivalence point = 7. The solubility of calcium sulfate anhydrite in mixed at room temperature. compounds derived from the reaction of a strong base with a weak acid or a strong acid with a weak base or a solution of a weak base and one of its salts. -Non metal ions from the acid and metal ions from the base combine to form a salt. B) H2SO4 (aq) + Ca (OH) 2 (aq) → CaSO4 (aq) + 2 H2O (l) Explanation: A is a reaction between a salt FeCl3 and a base KOH C is a n acid decomposing on it's own to form two products D is mercury, a metal reacting with oxygen. 2H2OGypsum [Hard solid] 14. is an acid reacting with a metal to liberate hydrogen. Antacids-Stomach produces a solution of hydrochloric acid with pH as low as 1. OH- as the only negative ion in solution. CaSO 4,Calcium Sulphate. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. 0058081736801913 mole. 472 M sulfuric acid was used to titrate a 0. Which of the following chemical reactions represents an acid-base reaction? a. To prepare a solution from a solid reagent, please use the Mass Molarity Calculator. When the water evaporates, the ions come together and becomes salt. See full list on swiflearn. Today we consider the chemistry of calcium carbonate, the main component of limestone rocks. How acidic or basic a substance is shown by its pH. If the pH of the solution is such that a particular molecule carries no net electric charge, the solute often has minimal solubility and precipitates out of the solution. This compound is Nitric Acid, a strong acid. Demonstration Procedure: I. CaSO 4,Calcium Sulphate. One of the most important reactions of acids and bases is their ability to neutralize one another. Assume that any other acid or base you encounter in this. All three beakers originally contained a suspension of brownish purple Cr(OH) 3 (s) (center). NH 4 Cl,Ammoinium chloride. And so, we can use the simplified version of the Bronsted-Lowry theory, the Arrhenius theory. NH4Cl, NH4 NO3 Basic Salts : Strong base + weak acid. The product is a complex or complex ion. - 16771696 kblimbaroc kblimbaroc 26. Word equation: Calcium oxide + Sulfuric acid → Water + Calcium sulfate. 5% to about 5. National Institutes of Health. Type of Chemical Reaction: For this reaction we have a double replacement reaction. asked • 05/28/19 Ca(OH)2+H2SO4=>CaSO4+H2O. It is result of evaporation of ancient ocean of million of years ago. A 2 M H3PO4, solution will have a Normality of 6N. Hence, the aqueous solution of ammonium sulfate is overall acidic. Acids and Bases. Also, due to formation of carbon dioxide gas, gas. 2H2O or mol The SI base unit for amount of substance is the mole. Use this page to learn how to convert between grams CaSO4. This answer is: 👍Helpful. CaSO4 is neather acid or base it is a salt which means it is nutreal. Metal + Acid = Salt + Hydrogen gas. c) Acids are compounds of hydrogen cations with an acidic residue: HNO3 - nitric acid; H2SO4 - sulfate acid; H3PO4 - phosphoric acid. Looking at the list of acids and bases at the top of the page you can imagine ALL the possibilities. With the question, which salts will be more soluble in an acidic solution than in pure water? As demonstrated above, insoluble salts with anions or a weak acid-base increase solubility while in strong acids than in pure water. Acids, Bases, and Ions Generally, a compound that is an acid or a base acts as an acid or a base only when it is dissolved in water. This compound is Calcium Sulfate, an ionic salt. In this reaction, energy is evolved in the form of heat and thus, such reactions are. ️📚👉 Watch Full Free Course:- https://www. The weak acids include most all acids, and the weak bases include all the non-hydroxide bases. So on hydrolysis, ammonium sulfate produces ammonium hydroxide and H2SO4. (Daily Double) 0. STRONG BASE. Methane (CH4í combines with oxygen to produce water and carbon dioxide. HCl + NaOH → NaCl + H2O The reaction is known as neutralization reaction. H 2 SO 4 + CaCl 2 CaSO4 + HCl d. 7 pH and pK a 8. txt) or view presentation slides online. (ii) Transfer a known volume of acid to an Erlenmeyer flask. H2SO4 (aq) + 2 KOH (aq) → 2 H2O (l) + K2SO4 (aq) Determine the volume (liters) of 0. Darmaidayxx and 3 more users found this answer helpful. Calcium sulfate (or calcium sulphate) is the inorganic compound with the formula CaSO 4 and related hydrates. This compound is Calcium Sulfate, an ionic salt. I'll tell you the ionic or Covalent bond list below. Brønsted in Denmark and T. What are the end products of a neutralization reaction? a) Gas, Salt b) Salt, water c) Water, Base d) Base, Salt Explanation Acids react with bases to give salt and water. 19 Description A Calcium salt of Acetic Acid, Calcium Acetate is a chemical substance having the chemical formula Ca (C2H3O2)2. Red color in Litmus. In chemistry, bases are substances that, in aqueous solution, are slippery to the touch, taste astringent, change the color of indicators (e. This is an acid-base reaction (neutralization): H2SO4 is an acid, Na2CO3 is a base. Acid-Base Reaction Examples. RTECSNumber : WS6920000. Mixing an acid with substances that are bases are examples of neutralization reactions. sodium chloride. 6HCl + 2Al \rightarrow 2 AlCl3 + 3H2. ACID + BASE -----> SALT + WATER. (NH 4)2SO 4 (s) → 2NH 4 ++ SO 4 2. Hi, CCl4 is called carbon tetrachloride, or more commonly - and in an abusive denomination - "tetrachloromethane" (abusive, as it is not methane, not even in part). d) Salts are metal compounds with an acidic residue: KNO3 - potassium nitrate; CaSO4 - calcium sulfate; K3PO4 - potassium orthophosphate; FeCl2 - ferric chloride. RTECSNumber : WS6920000. Darmaidayxx and 3 more users found this answer helpful. (c) Oxidation-Reduction: Ca(s) has an oxidation number of 0, while Ca2+(aq) has an oxidation number of +2—hence Ca is being oxidized. However, the conjugate base of the weak acid is a weak base and ionizes slightly in water. The weak acids include most all acids, and the weak bases include all the non-hydroxide bases. There are four different neutralization reactions: 1. When a base accepts a proton its conjugate acid is formed [e. 2H2O + CaSO4, were evaluated relative to the responses of …. Meaning, it cannot be dissolved in the solution of water. 2) Bases are bitter in taste, have soapy touch, turn red litmus blue and give hydroxide ions in solution. AlOH3, the conjugate base for Al3+, is a weak base and so Al3+ will be a. The salt of the weak acid or weak base Both must be present! 15. 8 x 10–1 H 2 C 2 O 4 (oxalic acid) HC 2 O 4 – 5. Acids Bases And Salts Chemical properties of Acids. 25 mL, find the final volume reading of the base. al(oh)3 + h2so4 → al2(so4)3 + h2o the table. CaO + H2SO4 → CaSO4 + H2O Acids react with bases to give salt and water. Strontium Iodide ( SrI2 ) is Ionic. Sulfuric acid - diluted, cold solution. H2OPlaster of Paris+H2OWater CaSO4. Sulfuric Acid - H 2 SO 4 Molar Mass of H2SO4 Oxidation Numbers of H2SO4 H2So4 Sulphuric Acid Battery Acid Hydrogen Sulfate Oil Of Vitriol [So2(Oh)2] [S(Oh)2O2] Products. time is linear and the. Video $$\PageIndex{1}$$: Chromium(III) Hydroxide [Cr(OH) 3 or Cr 2 O 3 •3H 2 O] is an Example of an Amphoteric Oxide. Strong and weak. A solution of hydrochloric acid (HCI) reacts with a solid calcium carbonate to produce water, carbon dioxide and calcium chloride. Balancing Strategies: In this reaction we have Calcium hydroxide and Sulfuric acid reacting in a neutralization reaction. K ALWAYS has a +1 charge. all amphiprotic substances are amphoprotic but no necesarily vice versa. heart outlined. For example, if a hydrogen atom, which consists of one proton and one. Since the calcium sulfate is insoluble in water, the coating acts as a protective layer thus preventing further attack on the metal by the acid. Safety and Handling. Strong Electrolytes : Essentially all ionic compounds and the strong acids. Which of the following chemical reactions represents an acid-base reaction? a. (Daily Double) 0. 3) A salt is a compound which is formed by neutralization reaction between an acid and base. is an acid-base reaction. Acids and Bases. Neutralization is the act of making an acidic or basic substance chemically neutral, meaning a pH of 7. Learn vocabulary, terms, and more with flashcards, games, and other study tools. 1 pH and TotPO4 = 0. Use these activities to study the vocabulary and major concepts presented in this chapter. There are virtually no molecules of a strong acid or base in solution, only ions. Neutral Salts : Strong Acid + Strong base pH value is 7 eg. Most important acid-base system in water, controls the pH of most waters Water exposed to the atmosphere dissolves carbon dioxide CO 2(g) creating carbonic acid H 2CO 3 CO 2(g) + H 20 ÆCO 2(aq) Gas dissolution CO 2(aq) + H 20 ⇔H 2CO 3 Carbonic acid formation Carbonic acid dissociates in two steps. Acid requirements are determined by (a) purity of the gypsum rock; and (b) qua:ity of the "anhydrite" desired. Acid compound. Also, due to formation of carbon dioxide gas, gas. NaOH is a base and HCl is an acid. (b) Acid-Base reaction: There is no change in oxidation number for any of the elements in this reaction—hence it is NOT an oxidation- reduction reaction. all amphiprotic substances are amphoprotic but no necesarily vice versa. The following reaction shows the products when sulfuric acid and aluminum hydroxide react. (pH)Strength of an Acid or Base A scale for measuring hydrogen ion concentration in a solution iscalled the pH scale pH scale measure ranges from 0-14 0 indicates highly acidic and pH 14 indicates highly basic nature of the solution Higher the hydronium ion concentration lower is the pH value pH of neutral solutions is 7 Values less than 7 indicate acidic nature and values greater than 7. The use of calcium sulfate (gypsum: CaSO4. Clear All strong acid Ba(C1O4)2 weak acid HC104 strong base CH3COOH weak base Ca(OH)2 soluble salt AgaCO3 insoluble salt Classify each of the following substances as either a strong or weak acid, strong or weak base, or a soluble or insoluble salt. Jacksepticeye Meme Time, "Experienced coaches that are well trained and take the classes with great patience. For the deprotonation of acids, K is known as K a, the acid dissociation constant. One of the first difficulties would be to get the application of a liquid focused. because PO4 has a charge of -3, it takes 3 K ions to neutralize the charge, thus, there are 3 K ions per phosphate ion: K3PO4. I'll tell you the ionic or Molecular bond list below. 472 M sulfuric acid was used to titrate a 0. Considering this, what type of reaction is Ca OH 2 h2so4 CaSO4 2h2o? This is an acid-base reaction (neutralization): H 2 SO 4 is an acid, Ca(OH) 2 is a base. What is the conjugate base of HSO4-? SO42- H2SO4 SO3 H2O I II III IV. And so, we can use the simplified version of the Bronsted-Lowry theory, the Arrhenius theory. The most straight-forward examples involving acids and bases deal with strong acids and bases. Strong acids, like HCl or HNO 3, are such good proton donors that none of their own molecules can remain in aqueous solution. The effect of the ionic medium on the formation constants was. Write the neutralization reaction between acids and bases in terms of the ions involved. Strong acids and strong bases are strong electrolytes [e. Which one is a strong acid?(a) NaOH (b) NH3 (c) CaSO4 (d) HNO3 Post Answer. Metal + Acid = Salt + Hydrogen gas. Answers: 2 Show answers Another question on Chemistry. l (d) amphoteric. Answer verified by Toppr. Calculate the degree of dissociation of acetic acid in its 0. AlOH3, the conjugate base for Al3+, is a weak base and so Al3+ will be a. Be sure to count all of the Hydrogen atoms on the reactants side of the equation. HCO3^- as the only negative ion in solution. What happens when baking powder is heated. It neutralize acidic character but does not impart noticeable basic character. (b) Both A and R are true but R is not the correct explanation of A. Nitric acid (a strong acid) Nitrous acid (a weak acid). H2SO4 is an acid, and Zn(OH)2 acts as a base. List ionic or Molecular bond. Define a back-titration. Since the calcium sulfate is insoluble in water, the coating acts as a protective layer thus preventing further attack on the metal by the acid. Find the similar compound on the other side of the reaction. Today we consider the chemistry of calcium carbonate, the main component of limestone rocks. 0mL of stock solution. A ssertion There is no change in the colour of litmus paper when brought in contact with distilled water. An indicators gives different colours in acid and base. Expert Answers gypsum or calcium sulphate CaSO4*2H2O (used in plaster casts), and sodium chloride. (The symbol , used for the acid dissociation constant, can lead to confusion with the association constant and it may be necessary to see the reaction. 1 M HCI on hot plate II. Calculate the degree of dissociation of acetic acid in its 0. (a) If excess CaSO4(s) is mixed with water at 25°C to produce a saturated solution of CaSO4, Chemistry In aqueous solution, hypobromite ion, BrO-, reacts to produce bromate ion, BrO3 -, and bromide ion, Br-, according to the following chemical equation. NH4Cl , MgCl2 are acidic salts. Acid Base Salts - Free download as Powerpoint Presentation (. If you know the Molarity of an acid or base solution, you can easily convert it to Normality by multiplying Molarity by the number of hydrogen (or hydroxide) ions in the acid (or base). Meaning, it cannot be dissolved in the solution of water. I'll tell you the ionic or Covalent bond list below. Since the calcium sulfate is insoluble in water, the coating acts as a protective layer thus preventing further attack on the metal by the acid. B) H2SO4 (aq) + Ca (OH) 2 (aq) → CaSO4 (aq) + 2 H2O (l) Explanation: A is a reaction between a salt FeCl3 and a base KOH C is a n acid decomposing on it's own to form two products D is mercury, a metal reacting with oxygen. CaSO4, K2CO3 are basic salts. Is CaSO4 Acid or Base ? CaSO4 is Neutral I'll tell you the Acid or Base or Neutral list below. The pKa value of CH3OH is more than 15. 472 M sulfuric acid was used to titrate a 0. List molecules Acid and Base. It is neither an acid or a base since it is a neutral salt. H334-H350-H317-H402-H412: May cause allergy or asthma symptoms or breathing difficulties if inhaled. National Center for Biotechnology Information. (ii) Acids react with oxides of metals while bases react with oxides of non-metals. 1 /2H2O +11 /2H2O -> CaSO4. In chemistry, bases are substances that, in aqueous solution, are slippery to the touch, taste astringent, change the color of indicators (e. 0 to 6) mol‚dm-3 tions. H2SO4(aq) + CaBr2(aq) → CaSO4(s) + 2HBr(g) asked Aug 15, 2019 in Chemistry by jrbryanp. Is CaSO4 an acid or base? Alkali salts or basic salts are salts that are the product of the neutralization of a strong base and a weak acid. HCO3^- as the only negative ion in solution. NH 4 Cl,Ammoinium chloride. A strong acid is an acid that ionizes completely in a solution of water and gives H+ ions and a weak acid is an acid that ionizes incompletely in a solution of water. NH 4 + is more acidic than SO 4 2-is basic, so (NH 4) 2 SO 4 is acidic. Acids are electrolytes they conduct electricity. Since the calcium sulfate is insoluble in water, the coating acts as a protective layer thus preventing further attack on the metal by the acid. Word equation: Calcium hydroxide + Sulfuric acid → Calcium sulfate + Water. May cause an allergic skin reaction. Key Points. The product is a complex or complex ion. NaOH is a base and HCl is an acid. This content was COPIED from BrainMass. com ️📚👉 Get Notes Here: https://www. EINECSNumber : 231-900-3. No H 3 O+ ions will be present, litmus changes colour only in the presence of H 3 O+ ions. This increases the amount of hydroxide ion in the solution produced in the reaction and renders it slightly basic. If the cation is the conjugate acid of a weak base or a relatively highly charged metal cation, however, it will react with water to produce an acidic solution. 2 Ca2+ and SO42-for solution 2 are less than for solution 1 because the ionic strength of solution 2 is greater than the ionic strength of solution 1, and as a result [Ca2+] and [SO 4 2-] must be larger in solution 2 for both solutions to satisfy the K sp expression. Stoichiometry Problems, Limiting Reagent, Acid/Base, Balancing Chemical Equations. There are four different neutralization reactions: 1. If the initial reading on the base buret was 63. Acid + Base Complex ion H + H + • •O 2 • • H H + H O H Example The acid-base bond is a coordinate covalent bond. Considering this, what type of reaction is Ca OH 2 h2so4 CaSO4 2h2o? This is an acid-base reaction (neutralization): H 2 SO 4 is an acid, Ca(OH) 2 is a base. Journal of Inorganic and Nuclear Chemistry 1975, 37 (5) , 1191-1202. com - View the original, and get the already-completed solution here! 1. The other strong acids are chloric acid, hydrobromic acid, sulfuric. 5H2O) nanoparticles using amorphous Ca-ethoxide as a precursor. 2 Brønsted-Lowry Acids and Bases 447 14. CaSO4 (used in plaster of Paris) Salt compound. Reactions with dilute hydrochloric acid All the metals react with dilute hydrochloric acid to give bubbles of hydrogen and a colourless solution of the metal chloride. When acids and bases are mixed together the reaction is called neutralization. H2SO4 is an acid, and Zn(OH)2 acts as a base. Write a chemical equation to show the reaction between Plaster of Paris and water. 52 x 10–3 Fe(H 2 O) 6 3+ Fe(H 2 O) 5 OH 2+ 1. 388 M barium hydroxide solution. 1 M HCI on hot plate II. 1 grams CaSO4. However, Sodium bicarbonate can act as either an acid or a base. You should also have your standardized NaOH saved from that lab. d) Salts are metal compounds with an acidic residue: KNO3 - potassium nitrate; CaSO4 - calcium sulfate; K3PO4 - potassium orthophosphate; FeCl2 - ferric chloride. Caso4 acid or base. National …. When titrating a strong monoprotic acid and KOH at 25 C, the: pH will be equal to 7 at the. • Strong acids • Strong bases • Most water soluble salts. When we use a weak base like baking soda on it we get relief. sp(CaSO4) = A Ca2+ A SO42- = [Ca 2+] Ca2+ [SO 4 2-] SO42-= 2. The chemistry of acids and bases, and details of acid-base titration analysis were covered in Experiment 18. mL of the base were required to neutralize the sample. The use of calcium sulfate (gypsum: CaSO4. The decrease of the thermal decomposition temperature of gypsum is induced by the presence of silica and is related to the surface acid-base interaction between SiO2 and CaSO4. 5L flask is maintained at 750 K along with a catalyst so that…. H2SO3 is Molecular bond. With sulfuric acid, the highly insoluble calcium sulfate is formed on the surface of the marble chip. When they both react with each other, it leads to the formation of two product namely sodium sulfate which is a salt and water. Brainly User. Calcium sulfate is used in the food industry as an anticaking agent, dough strengthener and stabilizer. CaSO4 , K2CO3 are basic salts. You should also have your standardized NaOH saved from that lab. Is caco3 an acid or base? calcium carbonate is a salt, it is neither acid nor base. NH4Cl , MgCl2 are acidic salts. What is a neutralization reaction? Give two examples. Best Answer. List molecules Acid and Base. Some chemical compounds are able to absorb the moisture from the surrounding's atmosphere. 2H2O + CaSO4, were evaluated relative to the responses of …. Which of the following chemical reactions will this be Li + CaCl LiCl + Ca?. (c) A is true but R … Continue reading Assertion and Reason Questions for Class 10 Science Chapter 2 Acids, Bases. 84 x 10–3 H 2 C 8 H 4 O 4 (o–phthalic acid) HC 8 H 4 O 4 – 1. Reactions in Aqueous Solutions Chapter 7 Sodium Reacting with Water. 5% to about 5. Neutralization reactions can make salts along with some other products. When the water evaporates, the ions come together and becomes salt. H2SO4 + Ca (OH) 2 -----CaSO4 + 2H2O. What is baking powder? Baking powder is formed by mixing edible acid-like tartaric acid with baking soda. (b) Both A and R are true but R is not the correct explanation of A. add solution to graduated cylinder with enough water to have 100 mL. Metal oxide + Acid → Salt + Water. Write the symbol for every chemical element that has atomic number greater than 3 and atomic mass less than 12. Properties of Acids. com - View the original, and get the already-completed solution here! 1. Transcribed image text: Classify each of the following substances as either a strong or weak acid, strong or weak base, or a soluble or insoluble salt. The weak acids include most all acids, and the weak bases include all the non-hydroxide bases. Strong acids, like HCl or HNO 3, are such good proton donors that none of their own molecules can remain in aqueous solution. Blue litmus becomes dry in presence of dry HCl gas. Dissolved in water, the pH will be slightly higher than 7, which is basic. Chemistry 12 Acids, Bases and Salts. This is an acid-base reaction (neutralization): H2SO4 is an acid, Na2CO3 is a base. Strong acids and strong bases are strong electrolytes [e. CaSO 4,Calcium Sulphate. Conjugate acids and bases: When an acid loses a proton, its product is called the conjugate base of that acid. NH4Cl , MgCl2 are acidic salts. However, the conjugate base of the weak acid is a weak base and ionizes slightly in water. The bases which dissolve in water to give OH- ions in solution are called alkalis, such as- NaOH, KOH, Ca(OH)2. AlOH3, the conjugate base for Al3+, is a weak base and so Al3+ will be a. Which means if the reaction is between a strong acid and weak base then its result will vary from the reaction between a strong acid and strong base or a weak acid and a weak base. 0 M nitric acid solution? 45. What is an ACID? pH less than 7 Neutralizes bases + Forms H ions in solution Corrosive-reacts with most metals to form hydrogen gas Good conductors of electricity. These H+ ions are responsible for the properties of acids. Sulfuric Acid - H 2 SO 4 Molar Mass of H2SO4 Oxidation Numbers of H2SO4 H2So4 Sulphuric Acid Battery Acid Hydrogen Sulfate Oil Of Vitriol [So2(Oh)2] [S(Oh)2O2] Products. Is CaSO4 an acid or base? Alkali salts or basic salts are salts that are the product of the neutralization of a strong base and a weak acid. (c) When sodium chloride is electrolysed, sodium is obtained at cathode which then reacts with water to give alkali and hydrogen. May cause an allergic skin reaction. Neutralization reactions can make salts along with some other products. Use these activities to study the vocabulary and major concepts presented in this chapter. Sometime pressure from deep inside the earth forces up large rocks to form salt like domes. sp(CaSO4) = A Ca2+ A SO42- = [Ca 2+] Ca2+ [SO 4 2-] SO42-= 2. typically the hydride of a non-metal anion. 0% by weight of the total initial charge of gypsum. 6HCl + 2Al \rightarrow 2 AlCl3 + 3H2. No, it means AlCl3 is a weak acid, because the only part of the molecule that is contributing to the pH of the solution is the Al+3 ion. In 1923, J. During a titration the following data were collected. Uses of plaster of Paris: Making toys, decorative material and smooth surfaces. More specifially the proton transfer view is know as the bronsted-lowry defincation of acids and base. We say they ionize. Sodium sulfide (Na2S) is an strong alkaline solution and is acidic in nature. Transcribed image text: Classify each of the following substances as either a strong or weak acid, strong or weak base, or a soluble or insoluble salt. Which is more soluble BaSO4 or CaSO4?. This content was COPIED from BrainMass. Why does dry HCl gas not change the colour of the dry litmus paper? a. Neutral Salts : Strong Acid + Strong base pH value is 7 eg. A weak acid and a weak base will produce any type of solution depending on the relative strengths of the acid and base involved. Red color in Litmus. time is linear and the. Question 5. example, the sour taste of lemons and other. Rather than being neutral (as some other salts), alkali salts are bases as their name suggests. No, it means AlCl3 is a weak acid, because the only part of the molecule that is contributing to the pH of the solution is the Al+3 ion. 2H2O is equal to 0. Rather than being …. NH4 as the only positive ion in solution. One of the first difficulties would be to get the application of a liquid focused. See full list on swiflearn. com/out/magnet-brains ️📚👉 Get All Subjects. How will you test the presence of this gas? Why do we pass hydrogen gas through soap solution why can't we burn it near the mouth of test tube and check it out by pop sound; What is the percentage of urea in detergents? Difference between weak base and. Bee sting or Nettle sting contains methanoic acid which causes pain and irritation. ; Colorless to dark-brown, oily, odorless liquid. Calculate the concentration of acetate ion in the solution and its p H. Video $$\PageIndex{1}$$: Chromium(III) Hydroxide [Cr(OH) 3 or Cr 2 O 3 •3H 2 O] is an Example of an Amphoteric Oxide. Showing 1-6 of 6 results for "CaSO4" Advanced Search. ph below 7. According to the following reaction, which molecule is acting as a base?. And so, we can use the simplified version of the Bronsted-Lowry theory, the Arrhenius theory. When they both react with each other, it leads to the formation of two product namely sodium sulfate which is a salt and water. 100g of sulfuric acid is reacted with 78g of calcium hydroxide. A strong acid is an acid that ionizes completely in a solution of water and gives H+ ions and a weak acid is an acid that ionizes incompletely in a solution of water. HBr + KOH KBr + H 2 O b. Given total component composition and pHinitial, calculate the acid or base to change the solution to a second pH, pHfinal (initially 8. 7 mL initial reading of acid = 60. Be sure to count all of the Hydrogen atoms on the reactants side of the equation. The product is a complex or complex ion. What happens when baking powder is heated. NaNO 3 and Na 2 CO 3 can be obtanied by nitric acid and carbonic acid respectively. (iii) Add three drops of chemical indicator to the acid. Strong and weak. CaSO4 synonyms, CaSO4 pronunciation, CaSO4 translation, English dictionary definition of CaSO4. ΑΣφ Submit Request Answer Part C Identify Sr(OH), (aq) as an acid or a base. 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https://courses.cs.cornell.edu/cs2800/wiki/index.php/SP20:Lecture_9_Diagonalization | # SP20:Lecture 9 Diagonalization
We gave several examples of proofs that set were Countable, and started an example showing that The power set of the naturals is uncountable.
# Countability
Definition: Countable
A set is countable if .
Equivalently, is countable of .
This last definition gives an intuitive definition of countability: if we have a surjection , then we can talk about could write , , etc., so that we can write in the form .
The fact that is surjective means that every element of is for some .
So the informal definition of countability is that is countable if its elements can be put in a (potentially infinite) sequence.
# Examples of countable sets
## ℕ ∪ {-1}
You might imagine the adding an element to a set makes it bigger. While this is true for finite sets, it is not true in general:
Proof:
Let be given by .
To see that is injective, choose arbitrary in and assume . Then so as required.
To see that is surjective, choose an arbitrary . Let . Since we have so . Moreover, as required.
## Even naturals
You might expect that the set of even natural numbers is smaller than the set of all natural numbers. But in fact, funny things happen with infinite sets:
Let be the set of even natural numbers. Then .
Proof: cardinality of evens
Let be given by . is clearly a well-defined function, because every element of the domain is of the form for exactly one . It is also clearly a bijection (details left as an exercise). Thus the evens and the naturals have the same cardinality.
## Integers
You might think that adding an infinite number of numbers to the set of natural numbers might make it bigger. But in fact, this is not (necessarily) so. The integers have the same cardinality as the natural numbers:
Proof: cardinality of the integers
The following image clearly defines a bijection:
Details are left as an exercise.
## ℕ ⨯ ℕ
You might imagine that the set of pairs of natural numbers is larger than the set of natural numbers, but in fact they can still be matched one-to-one:
Proof: │ℕ ⨯ ℕ│ = │ℕ│
Note: Although this proof creates a bijection by enumerating the elements on the diagonal, this technique is 'not' called diagonalization (which is used to prove that sets are uncountable). This often leads to confusion.
We wish to construct a bijection .
We can draw a table containing all pairs of natural numbers:
0 1 2
0 (0,0) (0,1) (0,2)
1 (1,0) (1,1) (1,2)
2 (2,0) (2,1) (2,2)
Now, giving a function is the same as giving a method for iterating through this table (identifying the 0th element, the 1th element, etc.). will be a bijection if we enumerate each pair exactly once.
To do so, we will start in the upper left hand corner, and then enumerate each pair along each diagonal, starting in the lower left, and ending in the upper right. For example, the first few pairs would be:
n f(n)
0 (0,0)
1 (1,0)
2 (0,1)
3 (2,0)
4 (1,1)
5 (0,2)
6 (3,0)
7 (2,1)
8 (1,2)
9 (0,3)
10 (4,0)
This pattern clearly hits each pair once, and doesn't hit any pair more than once, so it defines a bijection.
Note: I would consider this a complete and correct proof. It clearly defines a function, and explains why it is bijective. Some students have worried about the lack of clarity of the function.
To the address the former concern, we could write down a formula for this function. However, it is 'not' necessary to write down a formula for every function; indeed many functions do not have formulae at all. Rather, we must check that the function definition is unambiguous. A good way to reason about this informally is to ask "how would I go about computing f(73)?" If there is enough description to answer this question (and it will only give one answer!), the function is probably well defined.
If we wanted to provide more specificity on the bijectivity of the function, we could note that the function first lists every pair that sums to 0, then all pairs that sum to 1, and then all pairs that sum to 2, and so on. So a pair (a,b) will be on the (a+b)th diagonal (and will be the bth element of that diagonal).
# Examples of uncountable sets
At this point, you might suspect that all sets are countable. However, this is not the case.
## Diagonalization
A common technique to prove that a set is uncountable is called diagonalization.
The most famous examples of diagonalization are the proofs that the power set of the naturals is uncountable and the set of reals is uncountable.
To use diagonalization to prove that a set is uncountable, you typically do a proof by contradiction: assume that 'is' countable, so that there is a surjection , and then find a contradiction by constructing a diabolical object that is not in the image of . This contradicts the surjectivity of , completing the proof.
To construct , you typically imagine an (infinite) table describing : the row describes . In the table, you represent each element of as an infinite sequence of values; so that the table has a column for each natural number. The exact structure of the table depends on the set .
You then find by changing every value on the diagonal: you ensure that differs from in the th column. Since for all , , cannot be in the image of , so cannot be surjective.
## The set of subsets of the natural numbers
is uncountable.
Proof:
We use diagonalization to prove the claim. Suppose, for the sake of contradiction, that is countable. Then there exists a surjection .
We can imagine drawing as a table. For example, the first few outputs of might look like this:
i f(i)
0
1
2 the set of even numbers
3 the set of odd numbers
4
To put the sets into a common format, we might expand each set as a sequence of yes/no questions, with the th column of indicating whether :
i f(i)
0 (yes) yes yes yes yes
1 no (no) no no no
2 the set of even numbers yes no (yes) no yes
3 the set of odd numbers no yes no (yes) no
4 yes no no no (no)
Now, we construct a new diabolical set by changing each element on the diagonal. In this example, we have a "yes" in the 0th column of row 0 (meaning , so in our diabolical set we put a "no" in column 0 (by ensuring . Similarly, we have a "no" in row 1, column 1 (so ), so we put a "yes" in column 1 of (by placing ). Continuing in this fashion, we have
no yes no no yes
In general, we include if and only if . We can write this succinctly by defining . Note that although we used a specific example to figure out how to construct , this construction will work for an arbitrary .
Now, cannot be in the image of , because for any , differs from in the th column. If then , and if then . in either case, . Thus cannot be surjective, a contradiction. | 2021-10-25 11:15:36 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.958702802658081, "perplexity": 411.8380184909521}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587659.72/warc/CC-MAIN-20211025092203-20211025122203-00356.warc.gz"} |
https://tex.stackexchange.com/questions/609504/aspect-ratio-of-main-frame-of-beamer-is-not-changing-to-169 | # Aspect ratio of main frame of beamer is not changing to 16:9
I am new to beamer, and unfortunately, I am getting aspect ratio problem. I am working with beamer template warsaw by Till Tantau. It is working fine but I would like to use the landscape orientation. For that, I changed the aspect ratio in document settings--document class--custom--aspectratio=169, ,10pt. and I am using these packagers in the preamble;
\usepackage[orientation=landscape,size=custom,width=16,height=9,scale=0.5,debug]{beamerposter} %%%%self for aspect ratio
\usepackage{bookmark}
\hypersetup{bookmarksdepth=4,bookmarksnumbered=true,bookmarksopen=true}
\setcounter{tocdepth}{1}
% or ...
\setbeamercovered{transparent}
% or whatever (possibly just delete it)
%\usepackage{palatino}%
\usepackage[sc]{mathpazo}
%Set Presentation mode and colors
%--------------------------------------------------------
\mode<presentation> {
\usetheme{Warsaw}
\usefonttheme[onlysmall]{structurebold}
% default | professionalfonts | serif |
% structurebold | structureitalicserif |
% structuresmallcapsserif
}
%Using packages
%--------------------------------------------------------
\usepackage{amsfonts}\usepackage{amsxtra}\usepackage{pgf}
%\usepackage{german} %%I changed it
\usepackage{graphicx}
\usepackage{float}
\usepackage{multirow}
\usepackage{units}
%\usepackage{multimedia}
\usepackage{color}
\usepackage{colortbl}
\usepackage{booktabs}
\usepackage{hyphenat}
\usepackage{movie15}
\graphicspath{{./picture/}}
\include{defs}
\usepackage{animate}
%Begin of the document
%--------------------------------------------------------
\setbeamertemplate{frametitle}[default][left] %%for setting frame titles to the left
%%to change font size
%\usepackage{scrextend}
%\changefontsizes{10pt}
Now the problem is it is changing the aspect ratio of body text not the frame. Here is the example picture;
I believe that landscape orientation need to be applied by using following command:
% lscape.sty Produce landscape pages in a (mainly) portrait document.
\usepackage{lscape} ... \begin{landscape} ... \end{landscape}
You may refer to following articles: How to change certain pages into landscape/portrait mode
• thanks for the response, should In add these packages to preamble? Aug 4 at 9:55
• yes. I suggest use this package at header and try to leverage on this whenever you need to convert your writing to landscape rather than try to change the ratio. Aug 4 at 9:58
• Better try use it separately and share results Aug 4 at 10:04
• I am trying but don't know what should I add between \begin{landscape} ... \end{landscape} Aug 4 at 10:24
• That part of document that you need to be in landscape. you may leave landscape orientation in beamerposter and just insert your content in landscape tag Aug 4 at 10:28
To control the aspect ratio and also size of the presentation, you only have to use:
\geometry{paperheight=<whatever>,paperwidth=<whatever>}
Decreasing the paper dimensions you can have a (relatively) larger font or viceversa, so ideally you do not need even to touch the default font settings.
MWE:
\documentclass{beamer}
\usetheme{Warsaw}
\geometry{paperheight=4.5cm,paperwidth=8cm}
\begin{document}
\begin{frame}{foo}
foo
\end{frame}
\end{document}
• hey thanks for the response. But it is not working still getting the same result. Aug 5 at 0:05 | 2021-10-25 03:30:13 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4269430935382843, "perplexity": 3164.3645185614328}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-43/segments/1634323587623.1/warc/CC-MAIN-20211025030510-20211025060510-00474.warc.gz"} |
https://gamedev.stackexchange.com/questions/10003/graphics-module-am-i-going-the-right-way | # Graphics module: Am I going the right way?
I'm trying to write the graphics module of my engine. That is, this part of the code only provides an interface through which to load images, fonts, etc and draw them on the screen. It is also a wrapper for the library I'm using (SDL in this case).
Here are the interfaces for my Image, Font and GraphicsRenderer classes. Please tell me if I'm going the right way.
Image
class Image
{
public:
Image();
Image(const Image& other);
Image(const char* file);
~Image();
void free();
Image& operator=(const Image& other);
private:
friend class GraphicsRenderer;
void* data_;
};
Font
class Font
{
public:
Font();
Font(const Font& other);
Font(const char* file, int ptsize);
~Font();
void load(const char* file, int ptsize);
void free();
Font& operator=(const Font& other);
private:
friend class GraphicsRenderer;
void* data_;
};
GrapphicsRenderer
class GraphicsRenderer
{
public:
static GraphicsRenderer* Instance();
void blitImage(const Image& img, int x, int y);
void blitText(const char* string, const Font& font, int x, int y);
void render();
protected:
GraphicsRenderer();
GraphicsRenderer(const GraphicsRenderer& other);
GraphicsRenderer& operator=(const GraphicsRenderer& other);
~GraphicsRenderer();
private:
void* screen_;
bool initialize();
void finalize();
};
Edit: Some changes to the code and more details.
Per some of the discussions here I decided to replace my use of void* with something like this:
class Image
{
private:
struct ImageData;
std::shared_ptr<ImageData> data_;
};
(Obviously I'll do the same thing for the Font class.)
I should also mention hat these are not my final, complete classes. I only show here the basic functionality (loading and rendering). Instead of telling me what functionality you think I might need to add (rotating images, skewing, scaling, etc) just concentrate on reviewing what I already have. I'll try to defend my choices it I can, or change my approach if I cannot.
• Question: What sort of engine is this? What is the expected scope of the project? I'm a little worried that I might be giving poor advice based on a misconception of what you intended your project to do. Mar 21 '11 at 16:39
The thing that itches most for me is the void * 'abuse'.
Void-pointer: I don't need it. It's a way for me to limit the number of files that include SDL.h (void* data_ is just an SDL_Surface* cast to void*)
Well, you could avoid inclusion (which I approve BTW) by forward declarating it somewhere convenient for you.
• After some of the comments I decided that I will define a private struct FontData and have a std::shared_ptr<FontData> as a private member instead of the void*. This means I can avoid forward declaration too, which means there's no mention of the library in the header file. :) Mar 20 '11 at 21:24
• Ok, nice solution.
– jv42
Mar 21 '11 at 9:03
On Interfaces (in general)
You didn't give us interfaces, you gave us full class declarations. If these were interfaces, I would expect to see something like:
virtual bool load file(const char* file) = 0;
That, in C++, is an interface. I can override it in a subclass that implements functionality (in fact, I must!). If you are writing an interface, you are enforcing policy, and the above is how you do this.
Half of the complaints about usage of void * in the other answers would've been avoided if you had just exposed the interface functions, and kept the member variables hidden (as they should be, in an interface class).
Rawr.
On Interfaces (yours)
Image: Copying
You've got a copy constructor, and an equals operator. The issue I see here is that there is no good way of preventing the user from making silly extraneous copies of images.
For you, using SDL_surfaces, this is a big issue. Without meaning to be offensive, I'm willing to bet that you haven't considered what happens when you free an Image that is a duplicate of another image. I'm further willing to bet that you hadn't planned on handling full deep copying of the SDL_surface, and so in the aforementioned case you are likely to free an Image, and then your other copies of it will explode, killing everyone you love.
Solution: NO COPIES. Don't do it, don't allow it. Use a factory or a C-style loader function to create new instances of an Image, and use those instead of allowing copying or equals assignments. Alternately, completely figure out how to deep-copy an SDL_image (not super hard, but annoying).
Image: manipulation
How do I change your images once I've loaded them? According to your interface, I don't. Still, are you sure that is a good idea? How do I find out the bit-depth of an image? Its height? Width? Color space?
Font
How do I draw with this font? How do I get its name? How do I prevent the copying issues I complained about above? How do I set its color? Kerning? What about Unicode support?
Renderer: General
So, I notice you have a couple of blit*() functions, and also a render() function. This seems to imply that you want users to be able to queue up a bunch of blitting operations, and then flush them all to screen at once using the render() call.
That's fine; in fact, that's how my group's engine tech handles it too. :)
The use of a singleton here is acceptable, mostly because you seem to want to be letting the renderer have complete control of drawing things. If there is only one instance of it (as there probably should be), this won't hurt anything. Not what we do, but hey, it's a matter of taste.
There are a couple of big issues I see here, though.
Renderer: Transformations
You seem to be working only in 2D. That's fine. BUT...
How do you handle things like rotating an image when you draw it? Scaling it? You need full support for something called affine transformations. This allows you to easily rotate, scale, translate, skew, and otherwise frob in a pretty fashion images.
This needs to be supported (somehow) for both text and images.
Renderer: Coloring and Blending
I want to be able to blend colors onto my images, and set the colors for my text. You should expose this.
I also want to be able to do things like blend images when blitting, so I can do things like translucent ghosts or smoke or fire.
How to save yourself the trouble
Use SFML. It's got better design for, well, pretty much everything over SDL. They've already done what you are trying to do here. At the very least, look at how they've spec'ed their interfaces, and how they've designed their class hierarchy.
Also note that they address the issue of transforms I pointed out earlier in their Drawable class. And coloring. And blending.
They've got good tutorials and documentation, so it might be worth your time to fiddle with it a bit and get a feel for what your code should be able to accomplish.
Good luck!
• There are other stylistic decisions that you've been taken to task over (load() methods, void*, use of singletons, etc.) that, frankly, are completely overshadowed by the lack of functionality your proposed interface exposes. You shouldn't waste time worrying over what software development tropes you should be using when your software engineering here is so goddamn broken it makes my eyes bleed. Mar 21 '11 at 16:14
• You're off to a good start, you just need some more experience so you can learn to spot what functionality you are missing. Check out SFML, make some fun little apps, and then come back to this when you've got a clearer idea what capabilities you need to expose. Don't worry how ugly the plumbing is until you've got everything you need otherwise. Mar 21 '11 at 16:16
• Interface: Yes, it is an interface. It's the API kind of interface, not the virtual class type of interface. Void-pointer: Already sorted out. See my comments on jv42's answer. | Image copying: You make that assumption based on what? | Manipulation: A lot of details of the classes I haven't yet implemented or I considered only a distraction to the question. Also, you seem to be asking be for things like image rotation, getting the name of the font, etc. I'll implement those when and if the need arises, not now. [contd.] Mar 21 '11 at 21:06
• [cont.] SFML: Indeed, I just discovered this library and I like it a lot more. | Bottom line: What I've shown here is only the core (loading, and rendering). Other details I considered unimportant to show. Also, I won't start implementing any features (rotation, skewing, scaling) unless I later find I need them. It'll be easy to do that anyway. Mar 21 '11 at 21:09
• +1 for SFML. It'll get rid of most of this interface stuff with its API. :P Mar 21 '11 at 21:24
I'm a bit bothered by the "load" method, which breaks the Single-Responsibilty Principle (by the way, to the Communist Duck, I guess this is why he's using a const char*, because the SDL loading image function, coded in C, do not take a std::string). It shouldn't be an Image class' job to load itself, for at least two reasons :
• If you intend to optimize your memory use, you'll want to have specialized classes for loading resources.
• You'll handle exceptions more easily with a dedicated class.
• Load: No, it should be an Image class' job to load itself, the same way it's std::ifstream's job to load itself. This is not the place to do mem management: it will be done in a separate ResourceManager class. | Strings: It's not hard converting std::string to char*, so that's not the reason. the reason is simply that std::string would provide no advantage. Mar 21 '11 at 8:01
Singleton = BAD, remove immediately. Fonts and Images should not have a free() function, that should be the job of the destructor. The GraphicsRenderer should not offer those Blit functions, you should offer object-orientated classes which will provide a position for each end result, and the actual rendering automatically managed by the GraphicsRenderer. Finally, for encapsulation, use inheritance, not PIMPL, and definitely do not use a void*, use a strongly typed opaque pointer.
Here are some excerpts from my own design, although I've used compile-time switching and not run-time inheritance.
class D3D9Render
{
public:
std::shared_ptr<D3D9Font> CreateFont();
};
class D3D9Font
{
public:
// PUBLIC INTERFACE ---------------------------------------------------
std::unique_ptr<D3D9Text> CreateText();
int Height();
D3D9Font* Height(char newheight);
D3D9Font(D3D9Render& ref);
int Width();
D3D9Font* Width(char newwidth);
int Weight();
D3D9Font* Weight(short newweight);
bool Italic();
D3D9Font* Italic(bool newitalic);
string Font();
D3D9Font* Font(string str);
D3D9Font* CommitChanges();
};
class D3D9Text
{
public:
// PUBLIC INTERFACE ---------------------------------------------------
D3D9Text* Text(string str);
D3D9Text* PositionSizeX(short newx, short newxsize);
D3D9Text* PositionSizeY(short newy, short newysize);
D3D9Text* Font(std::shared_ptr<D3D9Font> ref);
D3D9Text* Colour(unsigned int newcolour);
string Text();
int PositionX();
int PositionY();
int SizeX();
int SizeY();
std::shared_ptr<D3D9Font> Font();
unsigned int Colour();
D3D9Text* CommitChanges();
};
Here, the memory is managed for you- all ownership is managed via smart pointing, and the interface is completely object orientated.
• Singleton: Singletons aren't bad if they're used right. Basically, the renderer hasn't any state to speak of so singleton is okay here (it's more complex than that, though). | Free: Deallocation is handled in the destructor. The free() function is there for the same reason the ifstream::close() function exists. | Blit: I'm trying to separate the data from the mechanism that uses the data. | Sprites: This is just the graphics module. Sprites are to be handled in the higher levels of the engine, in a manner similar to what you described. [contd.] Mar 20 '11 at 17:43
• [cont.] Inheritance: I don't understand how I could use inheritance here. | Void-pointer: Why shouldn't it be used? I thought it's a good way to limit the number of files that have access to the 3rd-party library. data_ is just an SDL_Surface* cast to void*. Whenever I use it I cast it back to SDL_Surface*. | Blit [contd.]: Another way of thinking about this is, the image doesn't draw itself — the renderer draws it. The image simply exists. Mar 20 '11 at 17:47
• Thanks for showing me std::shared_ptr, though. Thanks definitely going to come in handy. Mar 20 '11 at 18:12
• Free: depending the system, destroying the object and its associated resources (such as a texture) may need to happen in different threads, hence the need for a free() function; also, one could be using a custom allocation scheme that does not call the destructor. Mar 20 '11 at 18:14
• @DeadMG I'm also confused on how to provide encapsulation with inheritance. I always figured the best way to hide private members would be sticking to the strongly typed opaque pointer. Could you elaborate on your inheritance suggestion? Mar 20 '11 at 19:44
First things I can spot:
• Singletons are very very bad, usually. It's not 'Hm, do I only want one of these?' but more 'Hm, will more than one of these break the program?'.
• void* pointers are also rather risky. Why do you need one? Bad design somewhere.
• Font and Image seem to be closely related. Maybe you could take some of the functionality up the hierachy to a Renderable.
• I think this is me, but any reason why you're using const char* over std::string?
• Good spot on the const char*, I hadn't noticed that. Mar 20 '11 at 17:39
• Void-pointer: I don't need it. It's a way for me to limit the number of files that include SDL.h (void* data_ is just an SDL_Surface* cast to void*). | Strings: Do I have any reason not to use them? I don't do any manipulations, I just need a string. I'm free to use std::string outside of these classes, if I so desire. | Singletons: Yes, more than one GR will break my code. GR initializes SDL. Having it a singleton I don't have to worry about when SDL gets initialized or exited. Mar 20 '11 at 17:58
• The advantage of less files including SDL.h is pretty much zero. Somehow, I wouldn't have a renderer intialize SDL. I would abstract that to the main engine, or something else. What if you wanted other parts of SDL, except graphics? Mar 20 '11 at 18:20
• Other components: I would initialize them separately, in the components that need those parts. | Initialization: The main engine (GameManager, usually) shouldn't care about details such as what library I'm using. In my current setup I don't have to worry about initialization one bit, everything happens automatically (and is ensured to happen exactly when I need it to happen, not later, not sooner). | Header: Yes, there's no real technical advantage. I do find the code to be neater when the underlying library isn't exposed to me in the class interface, however. Mar 20 '11 at 18:30
• More of a thing that the only points I can see wrong with the design you have reasons for. I still stand by that singletons are not needed here, and that void pointers should be replaced with SDL_Surface ones. :P Mar 20 '11 at 19:03 | 2021-12-05 07:25:58 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.25056782364845276, "perplexity": 2483.2176053346666}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964363149.85/warc/CC-MAIN-20211205065810-20211205095810-00626.warc.gz"} |
https://walpolpo.wordpress.com/2010/01/ | # Another meeting?
Another killing weekly meeting next week before thesis audit. Minggu ini tiada meeting which is yahoooooo!!!!! But Jon will never leave us without work ( kilos of work !!!! )
• Corrected Thesis Audit Document; until now it seems that I am still working onsome amendments based on Jon’s comment
• Simple granuloma formation algorithm need to be discussed!!!!! —> adoi la…cammana? hopefully this week boleh concentrate dengan sharing energy!!!!!
• Then need to explain on extending according to signature based algorithm, have to write the algorithm and another week to extend the algorithm
Note to self: In order to add the chapter of a book that contains a collection of articles by different authors to a BibDesk database, use the template incollection.
Acrobat has a lot of great commenting tools, but what good are they if you can’t print them out? In Mac OS X, we use SKIM to print out comment ( Jon likes to add comments!!! )…So, if you find that your comments are not printing just follow these easy steps:
1. Open a PDF with comments
2. Go to File > Print
3. For the Comment and Forms option choose Document and Markup
4. You’ll see that the Preview Window now shows your comments and if you click Print you will now have a complete document with comments.
# How (and How Not) to write a technical paper:: Tips to myself (Part 1)
I would like to provide guidelines to myself. After writing qualifying dissertation, progress report, thesis audit and thesis outline. I have to prepare on writing my own thesis (the big book later). I am planning to start writing in a little while. The overall thesis structure is there but writing is a complicated process especially when English is not my first language, limited vocabulary and the difficulties in expressing what I really wanted to say. My assessor is very meticulous, every single sentences every single word, every single comma every single figure, leaving me with lots of frustration. It must look perfect for her, if I managed to feast her eyes in the documentations, she will be very happy. I want to write like them, I have to learn on how I can write and expressing my research so that they will understand. I never had any steps in writing, leaving me with lots of papers to refer, not sure about the content, everything is scattered in my memory. It’s time for a change I guess. It might be wrong, or not complete but then it is a good start for me.
I presume in writing, there are several steps
1. Preparation
2. Research
3. Organisation
4. Writing a draft
5. Revision
Preparation: Before I sat down to write this paper, I asked myself some questions, then, I discussed and asked Jon, to conform. Things that I need to clarify:
• the purpose of the document
• the audience
• the scope
Research: The purpose of the paper is to convey information. In order to convey information, I have to understand it. – but can I explain it?. This is a major problem….If don’t have the gist of the paper, that I cannot really explain it. Here, collection of references are needed and must be accurate.
Organisation: I understand that a poorly organised documentation may in fact be worse then I really thought it will be. I have to remember about what I need to tell users and how the information can best be conveyed. I need to choose the method that best suits my topics and my purpose. Fiona always mentioned that in writing you have to explain each sections and how the sections work together and general-to-specific writing manner. In general-to-specific writing manner, you begin with general/broad information about your research and move to more specific information in tha latter sections.
So now, I need to prepare an outline based on the organisation that I have in mind. This will provides a road map for my writing. Personally, I use an iterative approach: I start with a very broad outline as follow ( it’s not easy as I am stuck few times to relate each sections, to maintain coherence of the paper..:( ) I then go through my outline and break categories into sub-categories and sub-sub-categories until I feel I have a clear enough map.
• Introduction
• Swarm Robotics
• Fault Tolerance
• Swarm Taxis Algorithm
• Experimental Setup
• Initial Result
• Proposed Solution
• General Ideas
• Algorithm
• Conclusion
• References
Writing a draft: I am now ready to begin writing. I need to expand the outline into paragraphs. I save the introduction for last, so that I will have a better idea of what is covered in the body of the document. There is also a need to write a conclusion to the paper later – I should remember the basic rule of technical writing:
Tell them what you’re going to tell them. (Introduction)
Tell them. (Body)
Tell them what you’ve told them. (Conclusion)
Revision: Finally I need to check for completeness and accuracy.
• Check for conciseness, and covers a topic clearly.
• Check spelling and grammar. I use spell check
• Review abbreviations, acronyms, and initialisms expanded at their first usage?
Conclusion: So finally, I need to tell them what I’ve told them.
In preparing a technical paper, key points discussed were: establishing the purpose, assessing the audience, determining the scope, and selecting the appropriate medium. The research section covered the reasons for research and strategies for writing a paper. In organisation, methods of development were introduced such as division, classification, and general-to-specific writing manner. Outlining was also discussed. Finally, strategies for writing and revision were covered.
# Table issues…
I am writing to those who are facing the issues on displaying long table in latex. The default table environment in LaTeX does not work well if the data to be displayed in your table spans more than one page — the text cuts off and may flow outside of the normal page margins. The solution to this is to use the longtable package, which allows tables to take up multiple pages, and enables table row headings that span page breaks.
Declare the use of this package \usepackage{longtable} in the preamble, which should be installed already in your LaTeX setup. The skeleton of a long table looks like this:
\setlongtables % keeps the width uniform across both pages
\begin{longtable}{|c|c|c|c|}
\caption{Spurred species and their pollinators}\\
\hline
Flower species & Pollinator species & Family & Functional Group \\
\hline
Flower species & Pollinator species & Family & Functional Group \\
\hline \hline
{\it Aquilegia canadensis} & {\it Trochilus} & Trochil. & Bird \\
{ ….
……}
{\it Habenaria leucophaea} & {\it Chaerocampa} & Sphing. & Lepidoptera \\
\hline
\end{longtable}
# What have I been doing lately?
I have been busy, very ……..in the sense of lots of submission this month..including a thesis audit document, a conference paper and need to update code. The energy, aggregation, upgrade to 3.2, segmentation fault issues (which is just resolved)…alhamdulillah. Enjoy the movie, its only about robots. Based on the previous aggregation work that I have been doing in implementing the problems that I need to solve, I added few things to the simulation …including energy and a charger. Each robot are given a fixed energy, and if their energy is low, they will move to the charger which is on the left side. I am using pioneer2d robots, need to change to linuxbot and epucks later…finally, alhamdulillah all the issues are resolved and it works fine…
What’s next? we are planning to implement the following
1. lets update the algorithm in 3.2
2. the granuloma algorithm will be divided into few stages
• Implement energy reduction
• Isolate them
• charge
Lets’ hope next week will be progressive one!! enjoy!!!
I am planning to sleep real late today…since I need to prepare for my thesis outline documents…Soalan-soalan yang agak sukar di jawab….must have evidence for each and every questions, soalan sangat simple….jawapan sangat payah….:(
1. Is the overall content and structure of your thesis still as envisaged in your thesis proposal? [Any fresh topics, or abandoned topics? Any insertions, deletions or replacements in the chapter sequence?
1. Based on Thesis Outline that has been submitted, we proposed to have 7 chapters in the thesis. There is no fresh or abandoned topic included and the chapter sequence will remain the same. We include the structure of the thesis with this form to be discussed with supervisor and assessor for any amendment. (Need to prepare chapter summary for each and what I have done so far…to feast fiona’s eyes…she likes this!!!)
2. To what extent is your technical research work for the thesis?
3. What stage have you reached in writing the thesis? [Briefly indicate the state of each chapter — eg. first draft complete’, or to be based on a published paper’ or `not yet started’. Give an estimate of how long you will need to finish writing each chapter. Provide your assessor (and supervisor ifnecessary) with a copy of whatever thesis material you already have.]
4. How firm is your target submission date? [Express this as an interval: give the earliest and latest dates that you consider reasonable (barring miracles/disasters!).
1. Earliest sumission date will be on June 2011 and latest submission date will be on September 2011 ? I think So…:P
5. Is there any other aspect of the preparation of your thesis that you wish to comment on?
• Currently, all work is based on player/stage simulation. We estimate that work on real robots would start around April 2010, once we finished the simulation work.
Submitted the thesis documents to Jon today….alhamdulillah, waiting for feedback…need to update and prepare for discussion with both of them. boleh ZZZZzzzzzZZZZZZZ
# Writing a paper ….
I am struggling to write the paper… So first, I need to clarify what is the purpose of the paper and what I am going to do. This outline maybe useful in the future.
We are planning to write a paper to the 3rd IFIP Conference on Biologically-Inspired Collaborative Computing (BICC 2010). We plan to desrcibe on the experimental design and result that we have obtained so far. Based on our previous discussion, this paper highlights more on the analysis, literature and work in progress. Main contribution of the paper is to odentify what are the potential properties from immune systems that can be instantiated to the problem that we have in mind. In writing the paper, the first thing I should have to remember is to relate my paper with the conference theme….
Lets make this as exercise, a guideline to myself, so that I have a clearer mind in my writing
BRAINSTORMING
Writing abstract
When writing the abstract, some questions that I need to ask
• What is the purpose of my paper? This should, as with any abstract, be a general definition statement about the objectives of the paper.
• What approach am I using? I.e. am I reviewing the literature, describing a case study, supporting a research hypothesis, and if the latter, what is my research design and research methodology?
• What are my findings?
• What is the import of my findings?
Outline the content of the paper
General Questions that need to be answered in writing the paper.
• Part 1: Specify what problem (topic) is being addressed: Why is the problem (topic) interesting!
• Part 2: What is the current state of the art of solutions? Or, how is the topic currently being addressed in the literature?Why is the current literature inadequate?
• Part 3: What is the proposed solution?What is the motivation?Why is it interesting?
• Part 4: Discussion. How does the proposed solution compare with others? In theory? In practice? What are the weaknesses?
• Part 5: Conclusion. Summarize proposed solution and why it is interesting.Summarize weaknesses.Identify open questions.
RESPOND
# Collecting reference again
I realised my references are somehow outdated, and updation is required upon submission of my conference paper. Collection is tedious. 50% of references that I have collected in my first year is not referred at all since during my first year the area of research is still broad. It is a good idea when I started writing a conference paper in my third year as I start to look back on al the references that we have. Jon has suggested that we wrote a paper ( publishable or not every month, so I can start identify the hole in my research, things that I consider important or not should be identified prior to my thesis writing). Having the general outline of thesis is helpful, and as we move on we know which references are important and start writing literature on a specific title. I collected all the bibtex entry and update. Consistency is important while writing the entry, cannot really copy and paste it. I updated and collected my bibitem using BibDesk but for this conference, I have to rewrite since I have difficulties in getting the format that the LNCS provided, there is but it goes crazy with by .bib file. Below, is the seven standard styles in latex, I prefer to use the apa standard format (author, year) format
Seven standard style
Every computer with LaTeX comes with the following seven standard styles. While they work, we recommend the natbib interpretations below. NatBib is a citation package that standardizes citation commands across many different bibliography styles, so you can switch from using plain.bst to acm.bst without having to change your in-text citations.
plain.bst acm.bst ieeetr.bst alpha.bst abbrv.bst siam.bst | 2018-02-20 22:59:21 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.46621060371398926, "perplexity": 1962.4938675308092}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891813109.8/warc/CC-MAIN-20180220224819-20180221004819-00051.warc.gz"} |
https://sciprogramming.com/community/index.php?topic=1601.msg8979 | ### Author Topic: Hacking SQ1VGA with SCICompanion v3 (Read 23026 times)
0 Members and 1 Guest are viewing this topic.
#### spiffythedog
##### Hacking SQ1VGA with SCICompanion v3
« on: March 16, 2016, 05:53:55 AM »
Hello there,
I've been planning on making a small patch for Space Quest I VGA using SCICompanion v3 that fixes some typos ("That's a smell jet ack, all right, but for exploring space, you need a real ship.") and prevents the Time Pod from SQ4 from materializing on-screen after you take off in the mugger's spaceship. This latter change fixes a number of continuity issues with SQ4, as in that game the pod actually appears one screen to the right (just outside the loading bay for Droids B Us) and a considerable amount of time after Roger had left, enough time for Tiny to rebrand his business and for Droids B Us to file for Chapter XI. Simply removing the time pod animation from the scene ought to fix this.
I'm just having a bit of trouble trying to change/compile the script. I've isolated the room/script number (45) and I think I've identified the specific line(s) of script that needs to be modified. But the changed syntax makes it impossible for me to compile the script file and see whether it works or not in the actual game.
It's also quite apparent that I'm a complete noob at this, and am only interested in modifying existing games rather than building them from the ground up. Is there a specific tutorial that could help me out here?
#### Kawa
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #1 on: March 16, 2016, 06:15:32 AM »
Changed syntax shouldn't prevent compilation. What does prevent compilation is broken decompiles, like radar1::doVerb: CorruptFunction_CantDetermineCodeBounds. Putting a ; on that line will fix it, but kill any interactions with that prop. Another problem is that tiny::doVerb has odd cases, and is somewhat more difficult to fix without making the game unbeatable. Both of these appear no matter which language you decompile to.
Quote from: Decompiler
Decompiling script 45
ERROR: Invalid branch target.
Generated [REDACTED]\space quest 1\src\rm45.sc
Decompiled 29 of 29 functions successfully (100%).
Overall bytecount success rate: 100%.
Edit: The EGA version does better, with only one of these problems. Unfortunately, it's tiny::doVerb.
Edit?: I felt like a challenge, so I did it manually. Extracted 45.scr, used a hex editor and disassembly to change the last two states from 9 and 10 to the opposite order, effectively skipping the timepod.
Code: [Select]
code_126e: dup ; 3C ldi 9 ; 35 09, change to 0A eq? ; 1A, if not 9... bnt code_12af ; 30 3A 00, ...jump ahead to code_12af, the next case....code_12af: dup ; 3C ldi 10 ; 35 0A, change to 09The missing 'p' would go at 0x26CC in the extracted file.
« Last Edit: March 16, 2016, 09:29:34 AM by Kawa »
#### lskovlun
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #2 on: March 16, 2016, 12:31:06 PM »
This seems to be a regression - I tried it with an old version of Companion, and it worked fine...
EDIT: To clarify, "old" does not mean version 2, it means whatever beta version of v3 was current when I did this.
« Last Edit: March 16, 2016, 12:36:50 PM by lskovlun »
#### MusicallyInspired
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #3 on: March 16, 2016, 01:46:10 PM »
Which version? I've backed up every release until now. It's displayed in the About dialog.
#### lskovlun
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #4 on: March 16, 2016, 04:41:46 PM »
Looking closer, I can't even reproduce with the the latest version. Strange. Were there multiple versions of SQ! SCI? Is it choking on some change that spiffythedog was making?
#### Kawa
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #5 on: March 16, 2016, 04:54:13 PM »
It's not Spiffy's changes that choke it. It seems I have the same version as he, with the added twist of the EGA version choking on Tiny's changestate, too.
#### spiffythedog
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #6 on: March 17, 2016, 02:28:31 AM »
Changed syntax shouldn't prevent compilation. What does prevent compilation is broken decompiles, like radar1::doVerb: CorruptFunction_CantDetermineCodeBounds. Putting a ; on that line will fix it, but kill any interactions with that prop. Another problem is that tiny::doVerb has odd cases, and is somewhat more difficult to fix without making the game unbeatable. Both of these appear no matter which language you decompile to.
Quote from: Decompiler
Decompiling script 45
ERROR: Invalid branch target.
Generated [REDACTED]\space quest 1\src\rm45.sc
Decompiled 29 of 29 functions successfully (100%).
Overall bytecount success rate: 100%.
Edit: The EGA version does better, with only one of these problems. Unfortunately, it's tiny::doVerb.
Edit?: I felt like a challenge, so I did it manually. Extracted 45.scr, used a hex editor and disassembly to change the last two states from 9 and 10 to the opposite order, effectively skipping the timepod.
Code: [Select]
code_126e: dup ; 3C ldi 9 ; 35 09, change to 0A eq? ; 1A, if not 9... bnt code_12af ; 30 3A 00, ...jump ahead to code_12af, the next case....code_12af: dup ; 3C ldi 10 ; 35 0A, change to 09The missing 'p' would go at 0x26CC in the extracted file.
I altered the prescribed hex values in 45.scr like you said (09->0A, 0A->09) and fixed the typos. Now Tiny calls it a 'swell jetpack' like he should with no errors. However, altering the above values doesn't seem to do anything in my game, as the time pod animation still runs like usual. Also, the next couple of hex values after '3C 35 09' are '1A 30 0C 00' rather than '1A 30 3C 00' (I'll attach a copy of my 45.scr for reference).
If it helps, the interpreter version my copy of the game uses is apparently 'T.A00.081'.
#### Kawa
##### Re: Hacking SQ1VGA with SCICompanion v3
« Reply #7 on: March 17, 2016, 09:39:34 AM »
Gee, that was remarkably easy the second time 'round.
Also, the next couple of hex values after '3C 35 09' are '1A 30 0C 00' rather than '1A 30 3C 00'
Could be you edited the wrong changeState method? Because "3C, 35 09, 1A, 30 3A 00" means "dup, ldi 9, eq?, bnt 0x3A bytes ahead," and the next case jumps only 0x1C bytes ahead, to the end of the method, so I'm not sure where you got those branch distances. Editing the 45.scr you provided and being careful about it shows me the same jump distances I expected, at the same offsets I expected.
Code: [Select]
1270 3C 35 0A 1A 30 3A 00 39 42 78 39 FF 38 1E 01 78 dup, ldi $a, eq?, bnt$003a, pushi $42, push1, pushi$ff, pushi $011e,$push1 ... ^^- change from 0912B0 00 3C 35 09 1A 30 1C 00 39 2B 78 38 D1 01 39 06 ... dup, ldi $9, eq?, bnt$001c, pushi $2b, push1, pushi$01d1, pushi $6 ... ^^- change from 0A #### spiffythedog ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #8 on: March 17, 2016, 11:30:45 AM » That did it! I wasn't even looking at the right offsets, bugger it all. Thanks a million. I'll make sure you receive full credit for this. Anyway, after taking a good look at most of the in-game text, I was startled by the amount of glaring typos, repeated phrases, uncompleted fragments and formatting errors there were. This game clearly didn't receive as much QA as other Sierra games at the time. It could definitely use a bit of proofreading and revision, which I've already started. #### Kawa ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #9 on: March 17, 2016, 02:17:07 PM » Protip: those labels in the disassembly, code_126e and code_12af? Those are the actual offsets, minus two because resource type ID. So the dup opcodes (0x36) at those points are in the file at 0x1270 and 0x12b1 respectively. #### spiffythedog ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #10 on: March 19, 2016, 07:39:44 AM » Well, I've cleaned up/revised all of the text strings outside those contained in the script files themselves. Altering the script files is going to be a challenge for me, as while I can alter the text strings just fine with a hex editor (with a built in copy/paste function), the definitions of the string locations themselves will remain unchanged. Can anyone help me out with this? I've also made note of a number of other bugs/oddities that could probably be fixed: • A number of item interactions produce empty text boxes (e.g. use the bar coupon on the DBU coupon) • Offering the jetpack to the DBU salesbug prompts a regular grey text box instead of the salesbug's unique on-screen yellow text • When offering the DBU salesbug common items as payment for a droid, his text response spills off-screen and cannot be read • Tiny still negotiates the price of the ship after you've already bought it • Missing mechanical/'talking' sound effect when offering the DBU loading bay droid the bar coupon • No laser sound when shot in storage room (same for when shot by guard after missing big Sarien with gas grenade) • Smelling or tasting the Wally globes while they are inactive produces no sound or animation for death scene • Looking at certain objects on the same level as you gives the 'You can't see that from down here' message instead of the generic list of descriptions for Sarien doodads • Looking at same objects from higher level gives generic list of descriptions, as above (need to reverse?) • No sound for jumping into the waste disposal unit or when the armory droid crushes you with an anvil • Clicking eye icon on waste disposal chute when on lower level causes Roger to use the elevator and leave the screen • Sound of armory droid's footsteps briefly missing when he emerges from the back room • Armory droid's 'talking' sound effect plays for only about a millisecond after shooting him twice • Death sequence when giant Sarien warrior kills you is completely silent (got to be some way to remedy this, it just feels kind of cheap) #### Kawa ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #11 on: March 19, 2016, 11:17:13 AM » If the script file for a given bug decompiles cleanly, unlike #45, you're good to go. Tiny's negotiation for example is going to be a tough one. #### spiffythedog ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #12 on: March 21, 2016, 02:34:20 AM » It seems that altering ANY of the readily editable text strings in this game's script files with SCI Companion completely borks the integrity of the entire file. The locations of the 'look strings' for objects (and god knows what else) or possibly even the strings themselves don't appear to be shifted accordingly whenever I make a change in the editor and compile the script, resulting in garbled descriptions with the 'eye' icon or just plain corrupted text boxes. Is there something I'm not taking into account, here? #### Kawa ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #13 on: March 21, 2016, 04:18:15 AM » Is there something I'm not taking into account, here? You mean besides the fact that they're hard numbers and not the strings they should be? Nah, I think that's about it. #### troflip ##### Re: Hacking SQ1VGA with SCICompanion v3 « Reply #14 on: March 23, 2016, 07:06:48 PM » The corrupt script 45 appears to be due to a branch (bnt) instruction that jumps way out of bounds: Code: [Select] code_21fc: dup pushi$10a ; 266, doVerb push2 lsp param[$1] lsp param[$2] super Prop, $8 eq? bnt$f000
Could be interpreting the branch offset incorrectly, but Companion's disassembly is consistent with SV.exe (haven't checked ScummVM). My guess is that this case (the default case of the switch statement) is simply never reached in game, but there remains the question of how/why did Sierra's compiler output that bytecode?
Quote
Is there something I'm not taking into account, here?
How are you getting to room 45 when you test these changes? If this is from a save game that has script 45 loaded and is from an older version of the code, then there could be problems. This is more likely in SCI1.1 though, since you'll get the old heap resource (from the save game) mixed with the new script resource. But things can still go wrong in SCI1.0.
Check out my website: http://icefallgames.com
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https://electronics.stackexchange.com/questions/264306/microcontroller-hangs-while-switching-off | # Microcontroller hangs while switching off
In my application I have interfaced ESP8266 wifi chip with ATTiny828 micro-controller. We have developed our custom module with these two chips on it. The problem we are facing is that the micro-controller hangs sometimes when switching off the module. The button is the momentary type "push to On" switch and power ON/OFF functionality is implemented with the following circuit : when the switch is pressed npn transistor turns ON which in turn makes PMOS conduct current and makes the entire unit ON. As soon as the micro-controller gets started it puts ON/OFF pin in permanently HIGH state (to keep the unit powered on after the switch has been released). "SENSE" pin of the micro-controller senses the state of the switch (Pin change interrupts are active on this pin). So if the switch is pressed for more than a pre-programmed span of time, then micro-controller will make ON/OFF pin zero which will turn off the module.
we have taken care of debouncing in the software by adding delay of 100 ms. here is our code
// PW pin is same as "SENSE" pin
ISR(PCINT0_vect) {
static uint8_t tmr_pw_start = 0;
static uint8_t PW_prev = 1, GP2_prev = 1;
uint8_t const PW = READ(PW);
uint8_t const GP2 = READ(GPIO2);
if (PW != PW_prev) {
if (PW) { // Start measuring button press time
tmr_pw_start = 1;
ovf0 = 0;
} else if(tmr_pw_start){
if (ovf0 > 60) {
WRITE(On_off_pin, LOW); // POWER OFF
_delay_ms(100);
}
tmr_pw_start = 0;
}
}
if (GP2 != GP2_prev) {
TOGGLE(BLUE_LED);
}
PW_prev = PW;
GP2_prev = GP2;
}
ISR(TIMER0_OVF_vect, ISR_NOBLOCK) {
ovf0++;
if(!(ovf0 % 16)) TOGGLE(GREEN_LED);
}
We keep timer 0 always running and its number of overflows are used to measure elapsed time. it takes approx. 32 ms for one overflow to occur.
Other than this UART interrupts are also active in which it just takes the data and assigns it to a global variable.
The problem is this : By pressing the switch ON/OFF button for more than 2 seconds and then releasing it should switch off the unit which it does most of the time. But in 1 out of 15 cases micro-controller hangs while switching it off. It becomes unresponsive to button press and LEDs stop blinking. Or sometimes it becomes unresponsive with GREEN led still blinking.
Can anyone guess what can be the problem ?
• no idea, but change 100ms to 10ms and see if 1/15 changes probability... most momentary switches are <1ms unless really flakey – Tony Stewart Sunnyskyguy EE75 Oct 18 '16 at 22:26
• I can guess because I have seen this problem before with other processors. The problem you are experiencing can be caused by any number of issues. Most common is the way the voltage to the processor decays after you depower the regulator. It must be a razor sharp cutoff, or the processor will "misbehave" on the way down and set the ON/OFF signal back to ON. There are a number of other issues which I couldn't begin to guess without seeing your complete schematic. Start by checking out "snap-on-snap-off" voltage regulators (if they are still made by National Semi, or their heirs). – FiddyOhm Oct 18 '16 at 22:29
• What's the voltage of the ATTiny828 and ESP8266? Post-regulator, I mean. Is that 3.3V? Also, it reads like you are focused on the ATTiny and not the ESP8266. Have you tried to just pull the ESP8266 off of the circuit and see about the ATTiny functionality without it present? – jonk Oct 18 '16 at 22:40
• Why put the ATtiny behind your power switch at all? In power down mode, it typically needs 100nA. – Janka Oct 18 '16 at 22:41
• What is the type of ovf0? Is there a chance that it overflows if you are pressing the button too long? If so, that would cause the micro not to stop on the release, as the condition (ovf0 > 60) would be wrong. – Edesign Oct 19 '16 at 8:34
When you hold the button down and the micro drives the ON/OFF line low, there's a low-impedance path directly from the battery, through the I/O protection diodes on the SENSE pin of the micro, to its power bus — this is a very bad thing. There's another path through your external diode and the ON/OFF pin, too. | 2020-01-26 05:16:49 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.18947364389896393, "perplexity": 3037.0516117402376}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579251687725.76/warc/CC-MAIN-20200126043644-20200126073644-00447.warc.gz"} |
http://tex.stackexchange.com/questions/13272/hanging-references-using-fullcite | # Hanging references using \fullcite
I need APA style hanging references using \fullcite. For example
I need \fullcite because I want the reference cited where I want in the document, unlike at the end of the document using \cite.
How can I do this?
-
Update
The latest version of biblatex-apa (2.6 or above) now fixes this problem, so you should update rather than use the solution below. biblatex-apa now provides two commands: \fullcite which makes an inline reference (with no hanging indent) and \fullcitebib which makes a fake bibliography entry, with a hanging indent.
If you are making a categorised bibliography for a CV, for example, there are better ways to achieve this than using multiple \fullcitebib commands.
The problem is that the standard \fullcite command in biblatex assumes that the full citation should be included in the text. So what's needed is to redefine the \fullcite command so that it actually makes a small bibliography when called. Here is the code:
\documentclass{article}
\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage[style=apa]{biblatex}
\DeclareLanguageMapping{american}{american-apa}
\bibliography{biblatex-examples}
\DeclareCiteCommand{\fullcite}
{\renewcommand{\finalnamedelim}
\begin{thebibliography}\thebibitem}
{\usedriver
{\DeclareNameAlias{sortname}{default}}
{\thefield{entrytype}}\finentry}
{\thebibitem}
{\end{thebibliography}}
\begin{document}
\fullcite{reese} % This citation will appear in the text
%\printbibliography % if you also have a bibliography
\end{document}
This should now do what you want.
For multiple citations, the citations aren't sorted automatically, but appear in the order in the fullcite command. This is because the apa style sets sortcites=false; to get the \fullcites to be sorted you can add sortcites=true to your biblatex options, but I suspect this will make other citations not fully APA compatible.
I should mention that the \fullcite command is not really appropriate for making larger lists of references; biblatex has other ways to make partial bibliographies.
-
This one works, but I need APA style references. \usepackage[style=apa]{biblatex} does not work. – y2p Mar 13 '11 at 3:13
Sorry about that. I've updated my answer. Does this example work for you? – Alan Munn Mar 13 '11 at 5:11
This is what I had initially. But this does not give "hanging references". – y2p Mar 13 '11 at 5:42
Now I see. (If you had included this example in your question we might have progressed a little faster. :-) ). The problem is that the biblatex-apa doesn't define a \fullcite command, and so uses the biblatex default, which assumes that the reference should blend in with the rest of the text. What exactly are you trying to do with these \fullcites anyway? Maybe there's an alternative. – Alan Munn Mar 13 '11 at 5:46
Sorry about not putting it before, in the question? I need \fullcite to be able to put the whole citation in the document with other text. I want to be able to put text around these citations. Unlike doing, for example, [1] and the citation if at the end of the document. And these citations need to be hanging and in APA style – y2p Mar 13 '11 at 6:25 | 2015-05-25 21:48:13 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9306307435035706, "perplexity": 1987.5359718860389}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-22/segments/1432207928715.47/warc/CC-MAIN-20150521113208-00080-ip-10-180-206-219.ec2.internal.warc.gz"} |
https://www.kseebsolutions.com/kseeb-solutions-for-class-5-maths-chapter-8-part-1/ | # KSEEB Solutions for Class 5 Maths Chapter 8 Length
Students can Download Maths Chapter 8 Length Questions and Answers, Summary, Notes Pdf, KSEEB Solutions for Class 5 Maths helps you to revise the complete Karnataka State Board Syllabus and score more marks in your examinations.
## Karnataka State Syllabus Class 5 Maths Chapter 8 Length
### KSEEB Class 5 Maths Length Ex 8.1
Question 1.
How many millimeters make one centimeter?
10 millimeters
Question 2.
How many centimeters make one meter?
1m = 100cm
Question 3.
How many meters make one kilometer?
1 kilometre = 1000 metres
Question 4.
How many meters make half a kilometer?
500 meters
Question 5.
How many centimetres make $$\frac{3}{4}$$
= 75 centimeters
II. Solve the following:
Question 1.
Convert 573cm into meters.
1 meter = 100 Centimeter
573cm = 573/100 = 5.73
Question 2.
Convert 1,378m into kilometers.
1 kilometer = 1000 meter
1378 meter = 1378/1000
= 1.378 kilometer
Question 3.
Convert 1,515 cm into millimeters.
1cm = 10 millimeter
1515cm = 1515 × 10
= 15150 millimeter
Question 4.
Radha’s school is at a distance of 2,450m from her house. Express this distance in km.
1 kilometer = 1000 meter
Radha’s school is at a distance of 2,450mt
The distance in km = 2400/1000
= 2.450 kilometers
Question 5.
The length of a ground is 15 meters. Express the length in centimeters.
1 meter = 100 centimeter
The length of a ground = 15 meters
The length in centimeter = 100 × 15 = 1500
### KSEEB Class 5 Maths Length Ex 8.2
Question 1.
The length of a wire is 3m. What is the total length of 5 such wire?
The length of a wire is 3 meter The total length of 5 such wire = 5 × 3
= 15 meters
Question 2.
Out of a roll of cloth measuring 50m, 17m of cloth is sold. Find the length of the remaining cloth.
A roll of cloth measure 50 meters 17 meter of cloth is sold
The remaining length of cloth = 33 meter
Question 3.
24m of colored ribbon is distributed among 8 students equally. What is the length of the ribbon that each one gets?
The number of students = 8
The colored ribbons = 24 meter
Question 4.
How many centimeters are there in 9 meters?
1 metre = 100 centimetre
9 metre 100 × 9
= 900 centimeter
Question 5.
The length of a wooden plank is 19m. Out of this 5 pieces of 3tn each is cut off. Find the length of the remaining piece.
The length of a wooden plank = 19 metre
5 pieces of 3 metre each cut off = 5 × 3 = 15
The length of the remaining piece
= 19 – 15
= 4 meter
1. 22m 71cm and 14m 30cm
2. 4km 230m and 22km 280m
III. Subtract the following:
1. 68m 35cm from 75m 48cm
2. 12km 425m from 17km 650m
IV. Solve the following:
Question 1.
The length of a line segment is 12cm. Into how many line segments of 3cm each, can it be divided?
The length of a line segment = 12cm
Each line segment = 3cm
The length of each line segment = 4cm
2. Ravi bought 3m 60cm length of pant cloth. He gave lm 20 cm of cloth to his younger brother. What is the length of the remaining cloth?
Ravi bought of pant cloth – 3m, 60cm Ravi gave cloth to his younger brother . = 1m, 20cm
The length of the remaining cloth = ( 3m- lm) (60cm- 20cm)
= 2m, 40cm
Question 3.
The length of cloth purchased by John is as follows: 2m 20cm for shirt, 1m 20 cm for pant and 4m 80cm for coat. What is the total length of cloth purchased by John?
The length of cloth purchased by John
2 m 20cm for shirt
1 m 20cm for pant
4 m 80cm for coat
8 m 20 cm
1 m = 100 centimetre
Total length of cloth purchased by john = 8m, 20cm
Question 4.
2m 80cm of cloth is required to stitch a frock. What is the length of cloth required to stitch 12 such frocks?
To stitch a frock = 2m, 80cm
The length of cloth repaired to stitch 12
such frocks = 12 x 2 = 24
= $$\frac{12 \times 80}{960 \mathrm{cm}}$$
1 m = 100cm
960 cm = $$\frac{960}{100}$$ = 9.6m
24 metre + 9 metre + 60 cemtimetre 33 metres, 60 centimetres
Question 5.
The length of cloth required to stitch 6 pairs of Kurta and Pyjama is 33m. What is the length of cloth required to stitch 1 pair of Kurta & Pyjama?
Length of cloth required to stitch 6 pairs
of kurtha & pyjama = 33m
The length of cloth required to stitch are
pair of kurtha & pyjama $$\frac{33}{6}=5.5$$
Question 6.
The total length of 8 bundles of wire is 204m. Find the length of each bundle of wire.
The total length of 8 bundles of wire = 204m
The length of each bundle of wire
Question 7.
The hight of a table is 1 m 25cm and the height of a stool is 50cm less than the height of the table. Find the height of the stool. | 2021-09-23 00:04:52 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.586337685585022, "perplexity": 5717.168353759247}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-39/segments/1631780057403.84/warc/CC-MAIN-20210922223752-20210923013752-00469.warc.gz"} |
http://en.wikipedia.org/wiki/Cavitation_number | # Euler number (physics)
(Redirected from Cavitation number)
The Euler number (Eu) is a dimensionless number used in fluid flow calculations. It expresses the relationship between a local pressure drop e.g. over a restriction and the kinetic energy per volume, and is used to characterize losses in the flow, where a perfect frictionless flow corresponds to an Euler number of 1. The inverse of the Euler number is referred to as the Ruark Number with the symbol Ru.
It is defined as
$\mathrm{Eu}=\frac{p_\mathrm{upstream} - p_\mathrm{downstream}}{\rho V^2}$
where
• $\rho$ is the density of the fluid.
• $p_{\mathrm{upstream}}$ is the upstream pressure.
• $p_{\mathrm{downstream}}$ is the downstream pressure.
• $V$ is a characteristic velocity of the flow.
The cavitation number has a similar structure, but a different meaning and use:
The Cavitation number (Ca) is a dimensionless number used in flow calculations. It expresses the relationship between the difference of a local absolute pressure from the vapor pressure and the kinetic energy per volume, and is used to characterize the potential of the flow to cavitate.
It is defined as
$\mathrm{Ca}=\frac{p - p_\mathrm{v}}{\frac{1}{2}\rho V^2}$
where
• $\rho$ is the density of the fluid.
• $p$ is the local pressure.
• $p_\mathrm{v}$ is the vapor pressure of the fluid.
• $V$ is a characteristic velocity of the flow. | 2015-05-04 17:57:52 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 10, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7948664426803589, "perplexity": 501.93705876105884}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1430454709311.96/warc/CC-MAIN-20150501043149-00017-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://online.stat.psu.edu/stat414/book/export/html/778 | 24.2 - Expectations of Functions of Independent Random Variables
24.2 - Expectations of Functions of Independent Random Variables
One of our primary goals of this lesson is to determine the theoretical mean and variance of the sample mean:
$$\bar{X}=\dfrac{X_1+X_2+\cdots+X_n}{n}$$
Now, assume the $$X_i$$ are independent, as they should be if they come from a random sample. Then, finding the theoretical mean of the sample mean involves taking the expectation of a sum of independent random variables:
$$E(\bar{X})=\dfrac{1}{n} E(X_1+X_2+\cdots+X_n)$$
That's why we'll spend some time on this page learning how to take expectations of functions of independent random variables! A simple example illustrates that we already have a number of techniques sitting in our toolbox ready to help us find the expectation of a sum of independent random variables.
Example 24-1
Suppose we toss a penny three times. Let $$X_1$$ denote the number of heads that we get in the three tosses. And, suppose we toss a second penny two times. Let $$X_2$$ denote the number of heads we get in those two tosses. If we let:
$$Y=X_1+X_2$$
then $$Y$$ denotes the number of heads in five tosses. Note that the random variables $$X_1$$ and $$X_2$$ are independent and therefore $$Y$$ is the sum of independent random variables. Furthermore, we know that:
• $$X_1$$ is a binomial random variable with $$n=3$$ and $$p=\frac{1}{2}$$
• $$X_2$$ is a binomial random variable with $$n=2$$ and $$p=\frac{1}{2}$$
• $$Y$$ is a binomial random variable with $$n=5$$ and $$p=\frac{1}{2}$$
What is the mean of $$Y$$, the sum of two independent random variables? And, what is the variance of $$Y$$?
Solution
We can calculate the mean and variance of $$Y$$ in three different ways.
1. By recognizing that $$Y$$ is a binomial random variable with $$n=5$$ and $$p=\frac{1}{2}$$, we can use what know about the mean and variance of a binomial random variable, namely that the mean of $$Y$$ is:
$$E(Y)=np=5(\frac{1}{2})=\frac{5}{2}$$
and the variance of $$Y$$ is:
$$Var(Y)=np(1-p)=5(\frac{1}{2})(\frac{1}{2})=\frac{5}{4}$$
Since sums of independent random variables are not always going to be binomial, this approach won't always work, of course. It would be good to have alternative methods in hand!
2. We could use the linear operator property of expectation. Before doing so, it would be helpful to note that the mean of $$X_1$$ is:
$$E(X_1)=np=3(\frac{1}{2})=\frac{3}{2}$$
and the mean of $$X_2$$ is:
$$E(X_2)=np=2(\frac{1}{2})=1$$
Now, using the property, we get that the mean of $$Y$$ is (thankfully) again $$\frac{5}{2}$$:
$$E(Y)=E(X_1+X_2)=E(X_1)+E(X_2)=\dfrac{3}{2}+1=\dfrac{5}{2}$$
Recall that the second equality comes from the linear operator property of expectation. Now, using the linear operator property of expectation to find the variance of $$Y$$ takes a bit more work. First, we should note that the variance of $$X_1$$ is:
$$Var(X_1)=np(1-p)=3(\frac{1}{2})(\frac{1}{2})=\frac{3}{4}$$
and the variance of $$X_2$$ is:
$$Var(X_2)=np(1-p)=2(\frac{1}{2})(\frac{1}{2})=\frac{1}{2}$$
Now, we can (thankfully) show again that the variance of $$Y$$ is $$\frac{5}{4}$$:
Okay, as if two methods aren't enough, we still have one more method we could use.
3. We could use the independence of the two random variables $$X_1$$ and $$X_2$$, in conjunction with the definition of expected value of $$Y$$ as we know it. First, using the binomial formula, note that we can present the probability mass function of $$X_1$$ in tabular form as:
And, we can present the probability mass function of $$X_2$$ in tabular form as well:
Now, recall that if $$X_1$$ and $$X_2$$ are independent random variables, then:
$$f(x_1,x_2)=f(x_1)\cdot f(x_2)$$
We can use this result to help determine $$g(y)$$, the probability mass function of $$Y$$. First note that, since $$Y$$ is the sum of $$X_1$$ and $$X_2$$, the support of $$Y$$ is {0, 1, 2, 3, 4 and 5}. Now, by brute force, we get:
$$g(0)=P(Y=0)=P(X_1=0,X_2=0)=f(0,0)=f_{X_1}(0) \cdot f_{X_2}(0)=\dfrac{1}{8} \cdot \dfrac{1}{4}=\dfrac{1}{32}$$
The second equality comes from the fact that the only way that $$Y$$ can equal 0 is if $$X_1=0$$ and $$X_2=0$$, and the fourth equality comes from the independence of $$X_1$$and $$X_2$$. We can make a similar calculation to find the probability that $$Y=1$$:
$$g(1)=P(X_1=0,X_2=1)+P(X_1=1,X_2=0)=f_{X_1}(0) \cdot f_{X_2}(1)+f_{X_1}(1) \cdot f_{X_2}(0)=\dfrac{1}{8} \cdot \dfrac{2}{4}+\dfrac{3}{8} \cdot \dfrac{1}{4}=\dfrac{5}{32}$$
The first equality comes from the fact that there are two (mutually exclusive) ways that $$Y$$ can equal 1, namely if $$X_1=0$$ and $$X_2=1$$ or if $$X_1=1$$ and $$X_2=0$$. The second equality comes from the independence of $$X_1$$ and $$X_2$$. We can make similar calculations to find $$g(2), g(3), g(4)$$, and $$g(5)$$. Once we've done that, we can present the p.m.f. of $$Y$$ in tabular form as:
Then, it is a straightforward calculation to use the definition of the expected value of a discrete random variable to determine that (again!) the expected value of $$Y$$ is $$\frac{5}{2}$$:
$$E(Y)=0(\frac{1}{32})+1(\frac{5}{32})+2(\frac{10}{32})+\cdots+5(\frac{1}{32})=\frac{80}{32}=\frac{5}{2}$$
The variance of $$Y$$ can be calculated similarly. (Do you want to calculate it one more time?!)
The following summarizes the method we've used here in calculating the expected value of $$Y$$:
\begin{align} E(Y)=E(X_1+X_2) &= \sum\limits_{x_1 \in S_1}\sum\limits_{x_2 \in S_2} (x_1+x_2)f(x_1,x_2)\\ &= \sum\limits_{x_1 \in S_1}\sum\limits_{x_2 \in S_2} (x_1+x_2)f(x_1) f(x_2)\\ &= \sum\limits_{y \in S} yg(y)\\ \end{align}
The first equality comes, of course, from the definition of $$Y$$. The second equality comes from the definition of the expectation of a function of discrete random variables. The third equality comes from the independence of the random variables $$X_1$$ and $$X_2$$. And, the fourth equality comes from the definition of the expected value of $$Y$$, as well as the fact that $$g(y)$$ can be determined by summing the appropriate joint probabilities of $$X_1$$ and $$X_2$$.
The following theorem formally states the third method we used in determining the expected value of $$Y$$, the function of two independent random variables. We state the theorem without proof. (If you're interested, you can find a proof of it in Hogg, McKean and Craig, 2005.)
Theorem
Let $$X_1, X_2, \ldots, X_n$$ be $$n$$ independent random variables that, by their independence, have the joint probability mass function:
$$f_1(x_1)f_2(x_2)\cdots f_n(x_n)$$
Let the random variable $$Y=u(X_1,X_2, \ldots, X_n)$$ have the probability mass function $$g(y)$$. Then, in the discrete case:
$$E(Y)=\sum\limits_y yg(y)=\sum\limits_{x_1}\sum\limits_{x_2}\cdots\sum\limits_{x_n}u(x_1,x_2,\ldots,x_n) f_1(x_1)f_2(x_2)\cdots f_n(x_n)$$
provided that these summations exist. For continuous random variables, integrals replace the summations.
In the special case that we are looking for the expectation of the product of functions of $$n$$ independent random variables, the following theorem will help us out.
Theorem
If $$X_1, X_2, \ldots, X_n$$ are independent random variables and, for $$i=1, 2, \ldots, n$$, the expectation $$E[u_i(X_i)]$$ exists, then:
$$E[u_1(x_1)u_2(x_2)\cdots u_n(x_n)]=E[u_1(x_1)]E[u_2(x_2)]\cdots E[u_n(x_n)]$$
That is, the expectation of the product is the product of the expectations.
Proof
For the sake of concreteness, let's assume that the random variables are discrete. Then, the definition of expectation gives us:
$$E[u_1(x_1)u_2(x_2)\cdots u_n(x_n)]=\sum\limits_{x_1}\sum\limits_{x_2}\cdots \sum\limits_{x_n} u_1(x_1)u_2(x_2)\cdots u_n(x_n) f_1(x_1)f_2(x_2)\cdots f_n(x_n)$$
Then, since functions that don't depend on the index of the summation signs can get pulled through the summation signs, we have:
$$E[u_1(x_1)u_2(x_2)\cdots u_n(x_n)]=\sum\limits_{x_1}u_1(x_1)f_1(x_1) \sum\limits_{x_2}u_2(x_2)f_2(x_2)\cdots \sum\limits_{x_n}u_n(x_n)f_n(x_n)$$
Then, by the definition, in the discrete case, of the expected value of $$u_i(X_i)$$, our expectation reduces to:
$$E[u_1(x_1)u_2(x_2)\cdots u_n(x_n)]=E[u_1(x_1)]E[u_2(x_2)]\cdots E[u_n(x_n)]$$
Our proof is complete. If our random variables are instead continuous, the proof would be similar. We would just need to make the obvious change of replacing the summation signs with integrals.
Let's return to our example in which we toss a penny three times, and let $$X_1$$ denote the number of heads that we get in the three tosses. And, again toss a second penny two times, and let $$X_2$$ denote the number of heads we get in those two tosses. In our previous work, we learned that:
• $$E(X_1)=\frac{3}{2}$$ and $$\text{Var}(X_1)=\frac{3}{4}$$
• $$E(X_2)=1$$ and $$\text{Var}(X_2)=\frac{1}{2}$$
What is the expected value of $$X_1^2X_2$$?
Solution
We'll use the fact that the expectation of the product is the product of the expectations:
[1] Link ↥ Has Tooltip/Popover Toggleable Visibility | 2022-01-24 11:22:03 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9888024926185608, "perplexity": 109.475381187428}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320304528.78/warc/CC-MAIN-20220124094120-20220124124120-00521.warc.gz"} |
https://www.physicsforums.com/threads/power-rule.888162/ | Power Rule
Homework Statement
y=5-1/x
The attempt at a solution
y'=5-1/xln5(-1)(x-2/(x^2)
y'=-5-1/xx-2ln5/x2
But apparently my book says that the x^-2 should be -x^-2
That's what I don't understand. Some help please?
Mark44
Mentor
Your thread title, "Power Rule," doesn't apply to the function in this problem, which is in fact an exponential function.
Power rule: ##\frac d {dx}(x^n) = nx^{n - 1}##
Chain rule form of power rule: ##\frac d {dx}(u^n) = nu^{n - 1} \cdot \frac {du}{dx}##
Exponential function rule with chain rule: ##\frac d {dx}(e^u) = e^u \cdot \frac {du}{dx}##
Homework Statement
y=5-1/x
The attempt at a solution
y'=5-1/xln5(-1)(x-2/(x^2)
You have a mistake above -- that x-2 factor shouldn't be there.
quicksilver123 said:
y'=-5-1/xx-2ln5/x2
But apparently my book says that the x^-2 should be -x^-2
That's what I don't understand. Some help please?
You have the minus sign in -1. The book apparently shows it with -x-2. It's like -2 * 5 versus 2 * (-5) -- same result.
No, you misunderstand. I typed what I meant, minus the title error.
The -5 is supposed to be there, but IN ADDITION there is a negative in front of the x in the solution.
Solution from the book:
y'=5-1/x(ln5)[-1*(-x-2)]
Wolfram verifies the result from the book.
Ray Vickson
Homework Helper
Dearly Missed
Solution from the book:
y'=5-1/x(ln5)[-1*(-x-2)]
The book's solution is correct (although I would have written ##1/x^2## or ##x^{-2}## instead of ##(-1)(-x^{-2})##. Just use the fact that for constants ##c## and ##n## we have
$$\frac{d}{dx} c x^n = c n x^{n-1}.$$
Apply this to ##c=-\ln(5)## and ##n = -1##.
I just don't understand where the second negative comes from. I understand the negative one as that's the sign of the exponent, but what's the negative doing on x^-2? (-x^-2)
Because without the second negative sign to cancel out the first (the first being -1), my final answer is ending up as negative...
Mark44
Mentor
I just don't understand where the second negative comes from. I understand the negative one as that's the sign of the exponent, but what's the negative doing on x^-2? (-x^-2)
Because without the second negative sign to cancel out the first (the first being -1), my final answer is ending up as negative...
##y = 5^{-1/x} = (e^{\ln(5)})^{-1/x} = e^{-\ln(5)/x}##
##y' = e^{-\ln(5)/x} \cdot \frac d {dx}(-\ln(5)/x) = 5^{-1/x} \cdot \frac d {dx}(-\ln(5)/x)##
What do you get for the part I didn't finish?
quicksilver123
I dunno I haven't got to derivatives of logs in my book yet :(
Mark44
Mentor
I dunno I haven't got to derivatives of logs in my book yet :(
-ln(5) is a constant that multiplies 1/x. Surely you've seen a rule on how to differentiate a constant times a function.
Last edited:
quicksilver123
Thanks for your reply. Could I please get a step by step method that doesn't use Euler's number
Mark44
Mentor
I dunno I haven't got to derivatives of logs in my book yet :(
-ln(5) is a constant that multiplies 1/x. Surely you've seen a rule on how to differentiate a constant times a function.
Thanks for your reply. Could I please get a step by step method that doesn't use Euler's number
???
Post #8 is nearly complete, and goes step by step. All you have to do is differentiate -ln(5)/x. The last part of the equation I showed in post #8 doesn't involve e.
quicksilver123
SammyS
Staff Emeritus | 2021-07-24 08:59:56 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9440804719924927, "perplexity": 1501.1256762129783}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-31/segments/1627046150134.86/warc/CC-MAIN-20210724063259-20210724093259-00448.warc.gz"} |
http://mathhelpforum.com/calculus/46722-calculus-application-9th-edition-vs-8th.html | # Math Help - Calculus with Application 9th edition vs 8th
1. ## Calculus with Application 9th edition vs 8th
This book is from Lial, Greenwell and Ritchey. My Calculus class requires the 9th edition but I know from past experience that some of the books are the same the only difference would be the years. And I also know sometimes things do change. Can anyone confirm that this book is the same word for word as the 8th edition? It would save me a lot of money if I am able to use the 8th edition instead
2. Originally Posted by Sammyj
This book is from Lial, Greenwell and Ritchey. My Calculus class requires the 9th edition but I know from past experience that some of the books are the same the only difference would be the years. And I also know sometimes things do change. Can anyone confirm that this book is the same word for word as the 8th edition? It would save me a lot of money if I am able to use the 8th edition instead
i am pretty sure they are. especially when the editions get that high, 8th or 8th edition, nothing much changes. in anycase, the only problem you may have is the the pages may be numbered differently, as well as the problems. so your professor might say your homework is #4 on page 50 when in your edition it might be #2 on page 51, so be aware that you may have to tackle things like that. but as far as learning a topic from the text is concerned, there should be no difference.
the main reason for upgrading editions that many times, is to kill resale values, so you have to buy your text from the bookstore instead of your best friend, and the author and the bookstore makes more money. and don't let anyone tell you otherwise. if all the mistakes aren't caught by the 8th edition, then it's probably not that good a book to spend a lot of money on anyway, or the editors are incompetent
3. When I took intermediate algebra I thought I could save some money by buying an ealier edition. That turned out to be a pain due to either more problems were added or remove making every question out of order. I'm willing to take a chance and buy the 8th edition hoping everything is still numbered the same as the 9th edition.
4. Originally Posted by Sammyj
When I took intermediate algebra I thought I could save some money by buying an ealier edition. That turned out to be a pain due to either more problems were added or remove making every question out of order. I'm willing to take a chance and buy the 8th edition hoping everything is still numbered the same as the 9th edition.
I know calculus books usually don't change that much. i ahve seen the 4th, 5th and 6th edition of a calculus book that i used and nothing much changed. even the problem numbers were the same. they just added some more graphics and stuff. isn't there a way for you to compare them? where are you buying the 8th edition? where is the 9th sold?
5. The college wants $140 for the 9th edition but on ebay they are selling the 8th edition on average$25. If calculus really doesn't change I'm going to just get the 8th edition from ebay.
6. Originally Posted by Sammyj
The college wants $140 for the 9th edition but on ebay they are selling the 8th edition on average$25. If calculus really doesn't change I'm going to just get the 8th edition from ebay.
haha, yup. is \$115 worth the possible headache of (probably) having to copy a problem or two from my friends. to me it is!
7. Ok I'm going for it. Thanks! | 2014-03-11 22:54:35 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.33048367500305176, "perplexity": 516.6686339261902}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-10/segments/1394011338837/warc/CC-MAIN-20140305092218-00002-ip-10-183-142-35.ec2.internal.warc.gz"} |
https://support.bioconductor.org/p/108808/ | 5
5
Entering edit mode
@josephelsherbini-15796
Last seen 3.7 years ago
R version 3.4.3 (2017-11-30)
...
checking for gzeof in -lz... no
ERROR: configuration failed for package ‘ShortRead’
However, I do have libz available:
Sys.getenv()
...
-rw-rw-r-- 4 josephe josephe 153418 Jan 23 2017 /home/josephe/miniconda3/envs/dada2pipeline/lib/libz.a
lrwxrwxrwx 2 josephe josephe 14 May 11 12:30 /home/josephe/miniconda3/envs/dada2pipeline/lib/libz.so -> libz.so.1.2.11
lrwxrwxrwx 2 josephe josephe 14 May 11 12:30 /home/josephe/miniconda3/envs/dada2pipeline/lib/libz.so.1 -> libz.so.1.2.11
package installation shortread dependency • 7.2k views
1
Entering edit mode
@martin-morgan-1513
Last seen 14 days ago
United States
I'd ensure that this was seen by R, and that the header for libz (typically, installing the '-dev' version of the library) are available.
As a next step, if from the command line and with the unpacked source tarball available you try to install the package
> download.packages("ShortRead", ".", repos = BiocInstaller::biocinstallRepos())
> quit()
$tar xzf ShortRead_*gz$ cd ShortRead
ShortRead$R CMD INSTALL . and then look for config.log you'll see something like configure:2897: checking for gzeof in -lz configure:2922: gcc -o conftest -g -O2 conftest.c -lz >&5 configure:2922:$? = 0
configure:2931: result: yes
except that you won't get that result, and there'll be a conftest.c file and perhaps informative messages. I'd also look on the mailing list / support site for whatever 'conda' manager you're using for similar messages.
1
Entering edit mode
I get the error "cannot find -lz". Do you have any insight into that? I think I have zlib version 1.2.11 installed, it is in the directory /home/josephe/miniconda3/envs/dada2pipeline/lib, and my LD_LIBRARY_PATH is set to that directory.
configure:2897: checking for gzeof in -lz
configure:2922: /home/josephe/miniconda3/envs/dada2pipeline/bin/x86_64-conda_cos6-linux-gnu-cc -o conftest -march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-
protector-strong -fno-plt -O2 -pipe -DNDEBUG -D_FORTIFY_SOURCE=2 -O2 -Wl,-O2 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now conftest.c -lz >&5
collect2: error: ld returned 1 exit status
configure:2922: $? = 1 configure: failed program was: | /* confdefs.h */ | #define PACKAGE_NAME "" | #define PACKAGE_TARNAME "" | #define PACKAGE_VERSION "" | #define PACKAGE_STRING "" | #define PACKAGE_BUGREPORT "" | #define PACKAGE_URL "" | /* end confdefs.h. */ | | /* Override any GCC internal prototype to avoid an error. | Use char because int might match the return type of a GCC | builtin and then its argument prototype would still apply. */ | #ifdef __cplusplus | extern "C" | #endif | char gzeof (); | int | main () | { | return gzeof (); | ; | return 0; | } configure:2931: result: no configure:2941: error: zlib not found ADD REPLY 0 Entering edit mode You can see the command begin run (the stuff after the line configure:2922:) on the file echoed in the | comment. I'd guess it is that the LD_LIBRARY_PATH is either incorrect or not forwarded to the process that does the compilation and installation. You could edit the configure.ac file to echo what configure is seeing AC_INIT("DESCRIPTION") echo "LD_LIBRARY_PATH:$LD_LIBRARY_PATH"
AC_CHECK_SIZEOF([unsigned long]) AC_OUTPUT(src/Makevars)
then use autoconf and R CMD INSTALL; I have
ShortRead master$autoconf ShortRead master$ bioc-dev CMD INSTALL .
* installing to library '/home/mtmorgan/R/x86_64-pc-linux-gnu-library/3.5-Bioc-3.8'
* installing *source* package 'ShortRead' ...
LD_LIBRARY_PATH: /home/mtmorgan/bin/R-3-5-branch/lib:/usr/local/lib:/usr/lib/x86_64-linux-gnu:/usr/lib/jvm/java-9-openjdk-amd64/lib/amd64/server:/home/mtmorgan/bin/R-3-5-branch/lib:/usr/local/lib:/usr/lib/x86_64-linux-gnu:/usr/lib/jvm/java-9-openjdk-amd64/lib/amd64/server
If LD_LIBRARY_PATH is not correct, then I'm not really sure what to do -- I think it is really a conda problem.
0
Entering edit mode
I am also facing the same issue with R version 3.4.3 installed via anaconda3.5.2. Did you find any solution for this problem?
Thanks!
0
Entering edit mode
did you try to troubleshoot as above? what were the results?
0
Entering edit mode
Yes. No luck with that! Echoing LD_LIBRARY_PATH shows that anaconda lib is included. I am not sure why the package still can't find zlib.
checking for gzeof in -lz... no
0
Entering edit mode
Hi Martin,
I have the same problem with the same versions etc. I tried your troubleshooting method, but it just gives the same error that I get in the R console, the one posted above. This is also using conda. Installing ShortRead via conda will unfortuately downgrade R and some other things as I guess they don't have the current version yet.
3
Entering edit mode
I finally figured out setting CPPFLAGS and LDFLAGS works:
CPPFLAGS='-I/home/till/miniconda2/envs/dada2/include' LDFLAGS='-L/home/till/miniconda2/miniconda2/envs/dada2/lib'
What does NOT work however is
R CMD INSTALL --configure-args='--with-zlib-include=home/till//miniconda2/envs/dada2/include --with-zlib-lib=/home/till/miniconda2/envs/dada2/lib' .
0
Entering edit mode
Thanks for working on this. It sounds like a bioconda issue (I guess -- is that what creates the 'miniconda2' directory?), and that somehow R should know to look in the paths you indicate for the include and lib files. Can you pursue this 'upstream' with the bioconda team?
0
Entering edit mode
Could you please tell us what exactly you did?
This didn't work for me.
export CPPFLAGS="-I~/panases_soft/anaconda3.5.2/include"
export LDFLAGS="-L~/panases_soft/anaconda3.5.2/lib"
0
Entering edit mode
Just add those lines at configure:2889
CPPFLAGS='-I/home/miniconda3/envs/yourenvname/include'
LDFLAGS='-L/home/miniconda3/envs/yourenvname/lib'
1
Entering edit mode
Have you taken this issue up with the upstream conda installation that you are using? It needs to be fixed there rather than through fragile hacks like this.
0
Entering edit mode
Thank you! Thank you! This saved me tons of time!
1
Entering edit mode
olavur ▴ 10
@olavur-16765
Last seen 3.1 years ago
I had what seems to be the exact same problem, installing ShortRead in a conda environment. I was able to solve the problem for myself, so I hope this can help others having the same issue.
Long story short, this error seems to happen with zlib v1.2.11 but not zlib v1.2.8. So I made sure my environment was using this version:
$conda create -n myenv zlib=1.2.8 After this, installing ShortRead worked fine. $ source activate myenv
$R > source("https://bioconductor.org/biocLite.R") > biocLite("ShortRead") Note that it might be possible to downgrade zlib: $ conda install -c anaconda zlib=1.2.8
However, in my case this broke some other packages, which is why I had to create an entirely new environment. Hope this helps.
0
Entering edit mode
For what it's worth and in an attempt at a reproducible example, I did
sh ~/Downloads/Miniconda3-latest-Linux-x86_64.sh
conda create -n bioconductor bioconductor-biocinstaller
conda activate bioconductor
conda install bioconductor-shortread
In the failing configuration, if you clone the ShortRead package
git clone https://git.bioconductor.org/packages/ShortRead
cd ShortRead
and run
./configure
it should fail. Does it also report, in the config.log file that should now exist, a line like the one above,
...gnu/bin/ld: cannot find -lz
collect2: error: ld returned 1 exit status
? If so, can you further simplify the problem by creating a file conftest.c
/* confdefs.h */
#define PACKAGE_NAME ""
#define PACKAGE_TARNAME ""
#define PACKAGE_VERSION ""
#define PACKAGE_STRING ""
#define PACKAGE_BUGREPORT ""
#define PACKAGE_URL ""
/* end confdefs.h. */
/* Override any GCC internal prototype to avoid an error.
Use char because int might match the return type of a GCC
builtin and then its argument prototype would still apply. */
#ifdef __cplusplus
extern "C"
#endif
char gzeof ();
int
main ()
{
return gzeof ();
;
return 0;
}
and have it fail with
gcc conftest.c -lz
If so can you investigate the paths where libz is being sought
gcc -Wl,--verbose conftest.c -lz > conftest.log 2>&1
grep "libz.so" conftest.log
and compare these to where libz.so is found in the working environment. It is not, to my understanding, an issue about the library version, but rather how it is installed and discovered by conda.
0
Entering edit mode
In case anyone else comes along here searching for an answer:
I've played around with this a bit. It turns out that the problem is not with zlib at all; requiring zlib=1.2.8 ends up meaning that you need r-base<=3.4.1=1. Installing ShortRead also works with no problems in r-base=3.4.1=2, which requires zlib=1.2.11. At some point after that, they introduced changes in r-base which break installing packages with external dependencies.
I filed an issue at Conda-Forge with my findings.
1
Entering edit mode
@brendanfurneaux-13009
Last seen 22 months ago
I believe that the problem lies with the configuration of autotools in r-base>3.4.1b2, but I'm not competent to fix that. The plus side is that, although configure can't find zlib during the pre-installation, zlib is actually present in any Conda environment with r-base and can be linked during the actual installation. As I said in a comment above, I filed an issue at Conda-Forge. In the meantime, I made a fork of ShortRead which skips the check. It works for me with r-base=3.5.1.
tldr: remotes::install_github("brendanf/ShortRead")
0
Entering edit mode
Thank you for this, it was very helpful and worked wonderfully (I'm also using r-base=3.5.1). I'm glad I looked at the thread gain, two days ago, when I bumped into this issue, you had not shared your solution!
1
Entering edit mode
@january-weiner-4252
Last seen 2.7 years ago
European Union
It is sufficient to set the compilers -L flag to point to the conda's library. If you downloaded the ShortRead package to, say, ShortRead_1.38.0.tar.gz, your conda environment is called myconda and your conda installation is in /your/conda/directory/, then it is sufficient to run
conda activate myconda
export LDFLAGS="-L/your/conda/directory/envs/myconda/lib/"
0
Entering edit mode
Thans, it works!
Or we can still use following command after setting LDFLAGS:
> library(BiocManager)
This is my R and bioconductor version:
> BiocManager::install()
Bioconductor version 3.8 (BiocManager 1.30.4), R 3.5.1 (2018-07-02)
0
Entering edit mode
@panditaridaman-12995
Last seen 3.6 years ago
I had the same error for the past week. I made it to work by installing ShortRead in R (not in conda) and then add the core R's library when I ran R in conda environment. I just made it to work, so I am sure there might be a better solution. I think this is because of conflict in the zlib conda and core library.
Also posted the solution for the same question here:
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Use of this site constitutes acceptance of our User Agreement and Privacy Policy. | 2022-01-28 12:38:10 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.40130874514579773, "perplexity": 9449.227342682769}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320305494.6/warc/CC-MAIN-20220128104113-20220128134113-00622.warc.gz"} |
http://math.stackexchange.com/questions/432793/summing-a-series-with-a-changing-power | # Summing a series with a changing power
$$\sum_{r=0}^{k-1}4^r$$ Hi, I was wondering whether anyone could explain how to work this out. I know the end result is $\frac{4^k-1}{3}$, but I don't know why or how to get there. Thank you :D
-
It is a geometric sum. See in particular the section "formula" in the reference. – Mårten W Jun 30 '13 at 8:36
Ahh, I get it now, thanks :D – Elise Jun 30 '13 at 8:55
Multiply it by $(4-1)$. Expand without turning it into $4-1=3$. a lot of powers of $4$ will simplify except $4^k$ and $1$. Afterwards divide by $4-1=3$.
$4^{k-1}\times 4=4^{k}$. – Mlazhinka Shung Gronzalez LeWy Jun 30 '13 at 9:07
Okay, but why am I multiplying it by 4? Is the equation for this sum $\frac{a(r^n -1)}{r-1}$, with a=1, r=4 and n=k-1, if this is the case, why isn't the answer $\frac{4^(k-1) -1}{3}$ The 4 here is ment to be to the power of k-1 but I'm not too sure how to write that. Sorry for being so slow at this :S – Elise Jun 30 '13 at 9:13 | 2015-08-29 21:11:31 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.886137843132019, "perplexity": 410.690648033939}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-35/segments/1440644064538.31/warc/CC-MAIN-20150827025424-00228-ip-10-171-96-226.ec2.internal.warc.gz"} |
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Select two (2) questions to answer from the following list. Mn4-+ 8H+ Oxidation-Reduction & Electrochemistry Problem Set An oxidizing agent: a.receives electrons in a redox reaction. Just select your click then download button, and complete an offer to start downloading the ebook. CHM 112 Electrochemistry Practice Problems Answers Electrochemistry Problems 1) Given the E° for the following half-reactions: Cu+ + e-Æ Cu° E° red = 0.52 V Cu2+ + 2e-Æ Cu° E° red = 0.34 V What is E° for the reaction: Cu+ Æ Cu2+ + e- 2) How many Faradays are required to produce 21.58 g of silver from a silver Zumdahl Chemistry Study Questions Electrochemistry multiple choice questions answers. mmsphyschem.com Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T Page 2/8. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Answer the following questions using the text supplement for electrochemistry. Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T (273.15 25 ) K M mole R 8.31441.joulemole liter 1.K 1 Equations E std_cell E cathode E anode E cell E std_cell R.T n.F ln C anode C cathode. 1 mole 5 mole. d.more than one of the above is correct. Electrochemical Cell Worksheet Answers Electrochemical Cells Worksheet - Science Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T (273.15 25 ) K M mole R 8.31441.joulemole liter 1.K 1 Equations E std_cell E cathode E anode E cell E std_cell R.T n.F ln C anode C cathode. Olmsted 17.26 3. The problem that I am having at the moment is that I am not be able to get a proper CV shape (as you can see in the Fig 1) in the bare gold. 37 0 obj <>stream Calculate the volume of H 2(g) consumed during the same time period. 1. Once you have submitted your answers for grading, you cannot resubmit answers for the same Problem Set--you must click on Start each time you return to the Problem Set to be able to submit your answers. electrochemistry problems and answers.pdf FREE PDF DOWNLOAD NOW!!! It will not waste your time. (a) When the fuel cell operates at 25˚C and 1.00 atm for 78.0 minutes, 0.0746 mol of O Olmsted 17.25 2. Calculate the cell potential and free energy available for the following … Question: You Will Use Electrochemistry To Find The PK, Of CH-CH2COOH (phenylacetic Acid). Our library is the biggest of these that have literally hundreds of thousands of different products represented. Olmsted 17.25 2. Olmsted 17.33 5. (1) 2.4.2 Name ONE negative Copy your chosen questions or problems before answering them. Click Start to change the variable values in all questions. Thus, 3 mole of electrons are needed to reduce 1 mole of Al3+. I get my most wanted eBook. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. If you're having a hard time finding a good children's book amidst the many free classics available online, you might want to check out the International Digital Children's Library, where you can find award-winning books that range in length and reading levels. so many fake sites. Finally I get this ebook, thanks for all these Electrochemistry Problems And Answers I can get now! These are homework exercises to accompany the Textmap created for "General Chemistry: Principles and Modern Applications " by Petrucci et al. lol it did not even take me 5 minutes at all! Every electrochemical reaction must involve a chemical system in which at least one species is being oxidized and one species is being reduced. 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Calculate the cell potential and free energy available for the following electrochemical systems A voltaic cell with Mn/Mn2+ and Cd/Cd2+ half-cells has the following starting concentrations: [Mn2+] = 0.010 M and [Cd2+] = 0.100 M. a. Introduction to galvanic/voltaic cells. The half-reaction that occurs at the cathode during the electrolysis of molten sodium bromide is _____. Batteries are frequently made using solid electrodes. Electrochemistry Problems 1) Given the E° for the following half-reactions: Cu+ + e-Æ Cu° E° red = 0.52 V Cu2+ + 2e-Æ Cu° E° red = 0.34 V What is E° for the reaction: Cu+ Æ Cu2+ + e-2) How many Faradays are required to produce 21.58 g of silver from a silver nitrate solution? This set was written for "Honors Chemistry" which used Chemistry by Zumdahl and Zumdahl, 8th Edition (Brooks Cole, 2010). AP Chemistry: Electrochemistry Multiple Choice Answers AP Chemistry-Electrochemistry. What is the difference between an oxidation-reduction reaction and a half-reaction? 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If there is a survey it only takes 5 minutes, try any survey which works for you. Which is anode and which is the cathode? Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T (273.15 25 ) K M mole R 8.31441.joulemole liter 1.K 1 Equations E std_cell E cathode E anode E cell E std_cell R.T n.F ln C anode C cathode. Identify the choice that best completes the statement or answers the question. Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T (273.15 25 ) K M mole R 8.31441.joulemole liter 1.K 1 Equations E std_cell E cathode E … 19.4 O2-ions do not exist in aqueous solution. He sets up three different cells, and then compares the amount of energy generated from each one. AP REVIEW QUESTIONS – Electrochemistry - Answers 2007 part A, form B, question #3 2 H 2(g) + O 2(g) 2 H 2 O (l) In a hydrogen-oxygen fuel cell, energy is produced by the overall reaction represented above. Mn4-+ 8H+ 5e- → Mn2+ + 4H2O. Calculate the cell potential and free energy available for the following electrochemical systems Solutions for Electrochemistry Problem Set Page 1/5. The LibreTexts libraries are Powered by MindTouch ® and are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. eBook includes PDF, ePub and Kindle version. Olmsted 17.32 4. a.+4 b.-4 c.+7 d.0 Solution: (a) … I did not think that this would work, my best friend showed me this website, and it does! 1 a. Mn4-+ 8H+ h��T�n�@����F{�X�"AR�JIT%���xp��F�i��wfl����cƻޙ9s�k$H0 Thank you extremely much for downloading electrochemistry problems and answers.Most likely you have knowledge that, people have see numerous period for their favorite books when this electrochemistry problems and answers, but stop up in harmful downloads. You Set Up The Following Electrochemical Cell At 298 K: Th(s) | TH(NO.). The resulting $$\ce{[Fe^2+]}$$ value is -84.77 KJ so in this specific reaction, this is the desired $$\mathrm{\Delta G}$$. The following practice problems are to assist in your mastery of the topic of Electrochemistry. Al3+ + 3e- → Al. Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T (273.15 25 ) K M mole R 8.31441.joulemole liter 1.K 1 Equations E std_cell E cathode E anode E cell E std_cell R.T n.F ln C anode C cathode. (b) Oxidation occurs at the anode of a voltaic or an electrolytic cell. %PDF-1.3 %���� Give a reason for the answer. b.supplies electrons in a redox reaction. To get started finding Electrochemistry Problems And Answers , you are right to find our website which has a comprehensive collection of manuals listed. 00���� 30��ҙ��.���eZ�X����6H3�:@� g� Just invest little era to way in this on-line proclamation electrochemistry answers as well as review them wherever you are now. Q = 3 × F = 3 × 96500 = 289500 coulomb. Ten things to know before working electrochemistry problems: 1. Electrolytic Cells 38. Complementary General Chemistry question banks can be found for other Textmaps and can be accessed here.In addition to these publicly available questions, access to private problems bank for use in exams and homework is available to … Study Questions are chapter review problems with answers. Nernst Equation Example Problems. Correct answer: Silver has a more positive reduction potential than copper. What is the oxidation number of chlorine in dichlorine heptoxide? 2 - ELECTROCHEMISTRY 1. this is the first one which worked! Q = 3 × F = 3 × 96500 = 289500 coulomb. BF�����̂��e#�zP�gpy)�y�FUو���W�s9��E��E9(�b�����I���Ҽm�o_Ә7�!�����> ����:s\�S��~>V��O��Y*PRJ1��x.�����u��M�b��nRk���U���3�pX�&T�T�RޱÔ�L��m�R�ė&_�A�X%��.�D����]7J�u��w"OMZ�"���7��s Z�b�T[��Tl��z�oq6����(���B;��|P@�$뉗��/� ʀ�g3��"X����ב}�j���3�l�}{�����C�*�8�^>���.飇[��*�����>�̝t�:�P�� '�6���Sf��i������{���~���Ɇ}QO�$�6�WčX�Gkk/����椨�,gDI�!���W� �/p�^4�H�j� �!�D�&B������?��c�I"�6�1�VH�=�R�� !��3�N�7��������{{�W��3i?|&'���H�Ӯ�� ��� 1 a. write the net ionic reaction? MnO 4 − (aq) + H + (aq) + ClO 3 − (aq) → ClO 4 − (aq) + Mn 2+ (aq) + H 2 O (l) Give the balanced cell reaction and calculate E° for the cell. For each of the following reactions, identify which species is oxidized and which is reduced. UNIT 4 PROBLEM SET Redox Reactions and Electrochemical Cells 1. Oxidation-reductions reactions always have an electron transfer from the oxidized species to the reduced species. One of his cells is shown below as an example. Identify the oxidizing agent (OA) and the reducing agent (RA). I tried: I tried: 1. Specify whether the reaction will. This is an completely easy means to specifically … Electrodes and voltage of Galvanic cell. Rather than enjoying a good book with a cup of tea in the afternoon, instead they juggled with some malicious virus inside their desktop computer. (4 each) a) In highly acidic samples, the pH measured by glass electrode with a Ag/AgCl reference (with In an electrolytic cell (a type of electrochemical cell) the redox reaction that is carried out is a nonspontaneous reaction. Solutions for Electrochemistry Problem Set Constants: F 96484.56.coul .mole 1 T (273.15 25 ) K M mole R 8.31441.joulemole liter 1.K 1 Equations E std_cell E cathode E anode E cell E std_cell R.T n.F ln C anode C cathode. 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http://support.sas.com/documentation/cdl/en/stathpug/68163/HTML/default/stathpug_hpgam_details05.htm | # The GAMPL Procedure
Subsections:
#### Generalized Linear Models
All probability distributions that the GAMPL procedure fits are members of an exponential family of distributions. For the specification of an exponential family, see the section "Generalized Linear Models Theory" in Chapter 44: The GENMOD Procedure in SAS/STAT 14.1 User's Guide.
Table 7.11 lists and defines some common notation that is used in the context of generalized linear models and generalized additive models.
Table 7.11: Common Notation
Notation
Meaning
Log-likelihood
Penalized log-likelihood
Deviance
Penalized deviance
Response mean
Linear predictor
Dispersion parameter
Column of response variance
Prior weight for each observation
The GAMPL procedure supports the following distributions: binary, binomial, gamma, inverse Gaussian, negative binomial, normal (Gaussian), and Poisson.
For forms of log-likelihood functions for each of the probability distributions, see the section "Log-Likelihood Functions" in Chapter 44: The GENMOD Procedure in SAS/STAT 14.1 User's Guide. For forms of the deviance for each of the probability distributions, see the section "Goodness of Fit" in Chapter 44: The GENMOD Procedure in SAS/STAT 14.1 User's Guide.
Generalized additive models are extensions of generalized linear models (Nelder and Wedderburn 1972). For each observation that has a response and a row vector of the model matrix , both generalized additive models and generalized linear models assume the model additivity
where and is independently distributed in some exponential family. Generalized linear models further assume model linearity by for . Generalized additive models relax the linearity assumption by allowing some smoothing functions to characterize the dependency. The GAMPL procedure constructs the smoothing functions by using thin-plate regression splines. For more information about generalized additive models and other type of smoothing functions, see Chapter 41: The GAM Procedure in SAS/STAT 14.1 User's Guide.
Consider a generalized additive model that has some linear terms with coefficients and p smoothing functions . Each smoothing function can be constructed by thin-plate regression splines with a smoothing parameter . Using the notations described in the section Low-Rank Approximation, you can characterize each smoothing function by
Notice that each smoothing function representation contains a zero-degree polynomial that corresponds to a constant. Having multiple constant terms makes the smoothing functions unidentifiable. The solution is to include a global constant term (that is, the intercept) in the model and enforce the centering constraint to each smoothing function. You can write the constraint as
By using a similar approach as the linear constraint for thin-plate regression splines, you obtain the orthogonal column basis via the QR decomposition of such that . Each smoothing function can be reparameterized as .
Let and . Then the generalized additive model can be represented as . The roughness penalty matrix is represented as a block diagonal matrix:
Then the roughness penalty is measured in the quadratic form .
#### Penalized Likelihood Estimation
Given a fixed vector of smoothing parameters, , you can fit the generalized additive models by the penalized likelihood estimation. In contrast to the maximum likelihood estimation, penalized likelihood estimation obtains an estimate for by maximizing the penalized log likelihood,
Any optimization technique that you can use for maximum likelihood estimation can also be used for penalized likelihood estimation. If first-order derivatives are required for the optimization technique, you can compute the gradient as
If second-order derivatives are required for the optimization technique, you can compute the Hessian as
In the gradient and Hessian forms, and are the corresponding gradient and Hessian, respectively, for the log-likelihood for generalized linear models. For more information about optimization techniques, see the section Choosing an Optimization Technique. | 2017-10-17 19:24:39 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9050000905990601, "perplexity": 1046.6705015393547}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-43/segments/1508187822480.15/warc/CC-MAIN-20171017181947-20171017201947-00737.warc.gz"} |
http://math.stackexchange.com/questions/382437/evaluating-an-integral-by-using-du-dx | # Evaluating an integral by using du/dx
I am having trouble evaluating this formula. I have tried to solve it and got 1/4 as an answer. However by using the function Sf(x)dx in the Calc button in the TI-84 caclulator, I get 3.7037037 Which means my answer is wrong.
Here is the formuala that needs to be evaluated:
$\int_1^5 \frac {x}{\sqrt{3x+1}} dx$
one a side note I have : $$u = 3x+1$$ $$du/dx = 3$$ $$du = 3dx$$ $$x=(1/3)(u-1)$$ $$\begin{array}{c|lcr} x & u \\ \hline 5 & 16 \\ 1 & 4 \\ \end{array}$$
$\int_1^5 (x)(3x+1)^{-.5} dx$
(1/3)$\int_{16}^4 (1/3)(u-1)(u)^{-.5} du$
-
There are many ways to do this. One way is as follows: Let $\sqrt{3x+1} = t$, i.e., $3x+1 = t^2$, i.e., $x = \dfrac{t^2-1}3$. We then have $dx = \dfrac{2t dt}3$. Also, note that when $x=1$, we get $t=2$ and when $x=5$, we get $t=4$.
As per your substitution, i.e., $3x+1 = u$, we get $x = \dfrac{u-1}3$, i.e., $dx = \dfrac{du}3$. Also, as you have noted when $x=1$, we have $u = 4$ and $x=5$, gives us $u=16$. Hence, the integral becomes \begin{align} \int_1^5 \dfrac{x}{\sqrt{3x+1}}dx & = \int_4^{16} \dfrac{u-1}{3 \sqrt{u}} \dfrac{du}3 = \dfrac19 \int_4^{16} \left(\sqrt{u} - \dfrac1{\sqrt{u}}\right)du = \dfrac19 \left(\dfrac{u^{3/2}}{3/2}-\dfrac{u^{1/2}}{1/2}\right)_{u=4}^{u=16}\\ & = \dfrac29\left(\dfrac{16^{3/2}}3 - 16^{1/2} - \dfrac{4^{3/2}}3 + 4^{1/2}\right) = \dfrac29\left(\dfrac{64-8}3-2\right) = \color{red}{\dfrac{100}{27}} \end{align} | 2015-11-30 22:36:26 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 2, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9971529841423035, "perplexity": 143.153685576496}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-48/segments/1448398464253.80/warc/CC-MAIN-20151124205424-00095-ip-10-71-132-137.ec2.internal.warc.gz"} |
http://en.wikipedia.org/wiki/Bohr-Einstein_debates | # Bohr–Einstein debates
(Redirected from Bohr-Einstein debates)
Niels Bohr with Albert Einstein at Paul Ehrenfest's home in Leiden (December 1925)
The Bohr–Einstein debates were a series of public disputes about quantum mechanics between Albert Einstein and Niels Bohr, who were two of its founders. Their debates are remembered because of their importance to the philosophy of science. An account of the debates was written by Bohr in an article titled "Discussions with Einstein on Epistemological Problems in Atomic Physics".[1] Despite their differences of opinion regarding quantum mechanics, Bohr and Einstein had a mutual admiration that was to last the rest of their lives.[2]
## Pre-revolutionary debates
Einstein was the first physicist to say that Planck's discovery of the quantum (h) would require a rewriting of physics. As though to prove his point, in 1905 he proposed that light sometimes acts as a particle which he called a light quantum (see photon and wave–particle duality). Bohr was one of the most vocal opponents of the photon idea and did not openly embrace it until 1925.[3] The photon appealed to Einstein because he saw it as a physical reality (although a confusing one) behind the numbers. Bohr disliked it because it made the choice of mathematical solution arbitrary. He did not like a scientist's having to choose between equations.[4]
1913 brought the Bohr model of the hydrogen atom, which made use of the quantum to explain the atomic spectrum. Einstein was at first dubious, but quickly changed his mind and admitted it.
## The quantum revolution
The quantum revolution of the mid-1920s occurred under the direction of both Einstein and Bohr, and their post-revolutionary debates were about making sense of the change. The shocks for Einstein began in 1925 when Werner Heisenberg introduced matrix equations that removed the Newtonian elements of space and time from any underlying reality. The next shock came in 1926 when Max Born proposed that mechanics were to be understood as a probability without any causal explanation.
Einstein rejected this interpretation. In a 1926 letter to Max Born, Einstein wrote: "I, at any rate, am convinced that He [God] does not throw dice."[5]
Finally, in late 1927, Heisenberg and Born declared at the Solvay Conference that the revolution was over and nothing further was needed. It was at that last stage that Einstein's skepticism turned to dismay. He believed that much had been accomplished, but the reasons for the mechanics still needed to be understood.[4]
Einstein's refusal to accept the revolution as complete reflected his desire to see developed a model for the underlying causes from which these apparent random statistical methods resulted. He did not reject the idea that positions in space-time could never be completely known but did not want to allow the uncertainty principle to necessitate a seemingly random, non-deterministic mechanism by which the laws of physics operated. Einstein himself was a statistical thinker but disagreed that no more needed to be discovered and clarified.[4] Bohr, meanwhile, was dismayed by none of the elements that troubled Einstein. He made his own peace with the contradictions by proposing a principle of complementarity that emphasized the role of the observer over the observed.[3]
## Post-revolution: First stage
As mentioned above, Einstein's position underwent significant modifications over the course of the years. In the first stage, Einstein refused to accept quantum indeterminism and sought to demonstrate that the principle of indeterminacy could be violated, suggesting ingenious thought experiments which should permit the accurate determination of incompatible variables, such as position and velocity, or to explicitly reveal simultaneously the wave and the particle aspects of the same process.
The first serious attack by Einstein on the "orthodox" conception took place during the Fifth Solvay International Conference on Electrons and Photons in 1927. Einstein pointed out how it was possible to take advantage of the (universally accepted) laws of conservation of energy and of impulse (momentum) in order to obtain information on the state of a particle in a process of interference which, according to the principle of indeterminacy or that of complementarity, should not be accessible.
Figure A. A monochromatic beam (one for which all the particles have the same impulse) encounters a first screen, diffracts, and the diffracted wave encounters a second screen with two slits, resulting in the formation of an interference figure on the background F. As always, it is assumed that only one particle at a time is able to pass the entire mechanism. From the measure of the recoil of the screen S1, according to Einstein, one can deduce from which slit the particle has passed without destroying the wave aspects of the process.
Einstein's slit.
In order to follow his argumentation and to evaluate Bohr's response, it is convenient to refer to the experimental apparatus illustrated in figure A. A beam of light perpendicular to the X axis propagates in the direction z and encounters a screen S1 with a narrow (relative to the wavelength of the ray) slit. After having passed through the slit, the wave function diffracts with an angular opening that causes it to encounter a second screen S2 with two slits. The successive propagation of the wave results in the formation of the interference figure on the final screen F.
At the passage through the two slits of the second screen S2, the wave aspects of the process become essential. In fact, it is precisely the interference between the two terms of the quantum superposition corresponding to states in which the particle is localized in one of the two slits which implies that the particle is "guided" preferably into the zones of constructive interference and cannot end up in a point in the zones of destructive interference (in which the wave function is nullified). It is also important to note that any experiment designed to evidence the "corpuscular" aspects of the process at the passage of the screen S2 (which, in this case, reduces to the determination of which slit the particle has passed through) inevitably destroys the wave aspects, implies the disappearance of the interference figure and the emergence of two concentrated spots of diffraction which confirm our knowledge of the trajectory followed by the particle.
At this point Einstein brings into play the first screen as well and argues as follows: since the incident particles have velocities (practically) perpendicular to the screen S1, and since it is only the interaction with this screen that can cause a deflection from the original direction of propagation, by the law of conservation of impulse which implies that the sum of the impulses of two systems which interact is conserved, if the incident particle is deviated toward the top, the screen will recoil toward the bottom and vice-versa. In realistic conditions the mass of the screen is so large that it will remain stationary, but, in principle, it is possible to measure even an infinitesimal recoil. If we imagine taking the measurement of the impulse of the screen in the direction X after every single particle has passed, we can know, from the fact that the screen will be found recoiled toward the top (bottom), whether the particle in question has been deviated toward the bottom or top, and therefore through which slit in S2 the particle has passed. But since the determination of the direction of the recoil of the screen after the particle has passed cannot influence the successive development of the process, we will still have an interference figure on the screen F. The interference takes place precisely because the state of the system is the superposition of two states whose wave functions are non-zero only near one of the two slits. On the other hand, if every particle passes through only the slit b or the slit c, then the set of systems is the statistical mixture of the two states, which means that interference is not possible. If Einstein is correct, then there is a violation of the principle of indeterminacy.
Bohr's response was to illustrate Einstein's idea more clearly using the diagram in Figure C. (Figure C shows a fixed screen S1 that is bolted down. Then try to imagine one that can slide up or down along a rod instead of a fixed bolt.) Bohr observes that extremely precise knowledge of any (potential) vertical motion of the screen is an essential presupposition in Einstein's argument. In fact, if its velocity in the direction X before the passage of the particle is not known with a precision substantially greater than that induced by the recoil (that is, if it were already moving vertically with an unknown and greater velocity than that which it derives as a consequence of the contact with the particle), then the determination of its motion after the passage of the particle would not give the information we seek. However, Bohr continues, an extremely precise determination of the velocity of the screen, when one applies the principle of indeterminacy, implies an inevitable imprecision of its position in the direction X. Before the process even begins, the screen would therefore occupy an indeterminate position at least to a certain extent (defined by the formalism). Now consider, for example, the point d in figure A, where the interference is destructive. It is obvious that any displacement of the first screen would make the lengths of the two paths, a–b–d and a–c–d, different from those indicated in the figure. If the difference between the two paths varies by half a wavelength, at point d there will be constructive rather than destructive interference. The ideal experiment must average over all the possible positions of the screen S1, and, for every position, there corresponds, for a certain fixed point F, a different type of interference, from the perfectly destructive to the perfectly constructive. The effect of this averaging is that the pattern of interference on the screen F will be uniformly grey. Once more, our attempt to evidence the corpuscular aspects in S2 has destroyed the possibility of interference in F, which depends crucially on the wave aspects.
Figure C. In order to realize Einstein's proposal, it is necessary to replace the first screen in Figure A (S1) with a diaphragm that can move vertically, such as this proposed by Bohr.
It should be noted that, as Bohr recognized, for the understanding of this phenomenon "it is decisive that, contrary to genuine instruments of measurement, these bodies along with the particles would constitute, in the case under examination, the system to which the quantum-mechanical formalism must apply. With respect to the precision of the conditions under which one can correctly apply the formalism, it is essential to include the entire experimental apparatus. In fact, the introduction of any new apparatus, such as a mirror, in the path of a particle could introduce new effects of interference which influence essentially the predictions about the results which will be registered at the end."[citation needed] Further along, Bohr attempts to resolve this ambiguity concerning which parts of the system should be considered macroscopic and which not:
In particular, it must be very clear that...the unambiguous use of spatiotemporal concepts in the description of atomic phenomena must be limited to the registration of observations which refer to images on a photographic lens or to analogous practically irreversible effects of amplification such as the formation of a drop of water around an ion in a dark room.[citation needed]
Bohr's argument about the impossibility of using the apparatus proposed by Einstein to violate the principle of indeterminacy depends crucially on the fact that a macroscopic system (the screen S1) obeys quantum laws. On the other hand, Bohr consistently held that, in order to illustrate the microscopic aspects of reality, it is necessary to set off a process of amplification, which involves macroscopic apparatuses, whose fundamental characteristic is that of obeying classical laws and which can be described in classical terms. This ambiguity would later come back in the form of what is still called today the measurement problem.
In a recent experiment, an apparatus to test this debate was developed and implemented. The test consisted of a free-floating molecular double slit and the momentum change of the atom scattering from it. The results of this experiment were compared to quantum mechanical, and semi-classical models. The results revealed that the classical description of the slits, used by Einstein, provides a surprisingly good description of the experimental results, even for a microscopic system, if the momentum transfer is not ascribed to a specific pathway but shared coherently and simultaneously between both.[6]
### The principle of indeterminacy applied to time and energy
Figure D. A wave extended longitudinally passes through a slit which remains open only for a brief interval of time. Beyond the slit, there is a spatially limited wave in the direction of propagation.
In many textbook examples and popular discussions of quantum mechanics, the principle of indeterminacy is explained by reference to the pair of variables position and velocity (or momentum). It is important to note that the wave nature of physical processes implies that there must exist another relation of indeterminacy: that between time and energy. In order to comprehend this relation, it is convenient to refer to the experiment illustrated in Figure D, which results in the propagation of a wave which is limited in spatial extension. Assume that, as illustrated in the figure, a ray which is extremely extended longitudinally is propagated toward a screen with a slit furnished with a shutter which remains open only for a very brief interval of time $\Delta t$. Beyond the slit, there will be a wave of limited spatial extension which continues to propagate toward the right.
A perfectly monochromatic wave (such as a musical note which cannot be divided into harmonics) has infinite spatial extent. In order to have a wave which is limited in spatial extension (which is technically called a wave packet), several waves of different frequencies must be superimposed and distributed continuously within a certain interval of frequencies around an average value, such as $\nu_0$. It then happens that at a certain instant, there exists a spatial region (which moves over time) in which the contributions of the various fields of the superposition add up constructively. Nonetheless, according to a precise mathematical theorem, as we move far away from this region, the phases of the various fields, at any specified point, are distributed causally and destructive interference is produced. The region in which the wave has non-zero amplitude is therefore spatially limited. It is easy to demonstrate that, if the wave has a spatial extension equal to $\Delta x$ (which means, in our example, that the shutter has remained open for a time $\Delta t = \Delta x/v$ where v is the velocity of the wave), then the wave contains (or is a superposition of) various monochromatic waves whose frequencies cover an interval $\Delta \nu$ which satisfies the relation:
$\Delta \nu \ge \frac{1}{\Delta t}.$
Remembering that in the universal relation of Planck, frequency and energy are proportional:
$E = h\nu \,$
it follows immediately from the preceding inequality that the particle associated with the wave should possess an energy which is not perfectly defined (since different frequencies are involved in the superposition) and consequently there is indeterminacy in energy:
$\Delta E = h\,\Delta\nu \ge \frac{h}{\Delta t}.$
From this it follows immediately that:
$\Delta E \, \Delta t \ge h$
which is the relation of indeterminacy between time and energy.
### Einstein's second criticism
Einstein's thought experiment of 1930 as designed by Bohr. Einstein's box was supposed to prove the violation of the indeterminacy relation between time and energy.
At the sixth Congress of Solvay in 1930, the indeterminacy relation just discussed was Einstein's target of criticism. His idea contemplates the existence of an experimental apparatus which was subsequently designed by Bohr in such a way as to emphasize the essential elements and the key points which he would use in his response.
Einstein considers a box (called Einstein's box; see figure) containing electromagnetic radiation and a clock which controls the opening of a shutter which covers a hole made in one of the walls of the box. The shutter uncovers the hole for a time $\Delta t$ which can be chosen arbitrarily. During the opening, we are to suppose that a photon, from among those inside the box, escapes through the hole. In this way a wave of limited spatial extension has been created, following the explanation given above. In order to challenge the indeterminacy relation between time and energy, it is necessary to find a way to determine with adequate precision the energy that the photon has brought with it. At this point, Einstein turns to his celebrated relation between mass and energy of special relativity: $E=mc^2$. From this it follows that knowledge of the mass of an object provides a precise indication about its energy. The argument is therefore very simple: if one weighs the box before and after the opening of the shutter and if a certain amount of energy has escaped from the box, the box will be lighter. The variation in mass multiplied by $c^2$ will provide precise knowledge of the energy emitted. Moreover, the clock will indicate the precise time at which the event of the particle’s emission took place. Since, in principle, the mass of the box can be determined to an arbitrary degree of accuracy, the energy emitted can be determined with a precision $\Delta E$ as accurate as one desires. Therefore, the product $\Delta E \Delta t$ can be rendered less than what is implied by the principle of indeterminacy.
George Gamow's make-believe experimental apparatus for validating the thought experiment at the Niels Bohr Institute in Copenhagen.
The idea is particularly acute and the argument seemed unassailable. It's important to consider the impact of all of these exchanges on the people involved at the time. Leon Rosenfeld, a scientist who had participated in the Congress, described the event several years later:
It was a real shock for Bohr...who, at first, could not think of a solution. For the entire evening he was extremely agitated, and he continued passing from one scientist to another, seeking to persuade them that it could not be the case, that it would have been the end of physics if Einstein were right; but he couldn't come up with any way to resolve the paradox. I will never forget the image of the two antagonists as they left the club: Einstein, with his tall and commanding figure, who walked tranquilly, with a mildly ironic smile, and Bohr who trotted along beside him, full of excitement...The morning after saw the triumph of Bohr.
The "triumph of Bohr" consisted in his demonstrating, once again, that Einstein's subtle argument was not conclusive, but even more so in the way that he arrived at this conclusion by appealing precisely to one of the great ideas of Einstein: the principle of equivalence between gravitational mass and inertial mass. Bohr showed that, in order for Einstein's experiment to function, the box would have to be suspended on a spring in the middle of a gravitational field. In order to obtain a measurement of weight, a pointer would have to be attached to the box which corresponded with the index on a scale. After the release of a photon, weights could be added to the box to restore it to its original position and this would allow us to determine the weight. But in order to return the box to its original position, the box itself would have to be measured. The inevitable uncertainty of the position of the box translates into an uncertainty in the position of the pointer and of the determination of weight and therefore of energy. On the other hand, since the system is immersed in a gravitational potential which varies with the position, according to the principle of equivalence the uncertainty in the position of the clock implies an uncertainty with respect to its measurement of time and therefore of the value of the interval $\Delta t$. A precise evaluation of this effect leads to the conclusion that the relation $\Delta E \Delta t \ge h$ cannot be violated.
## Post-revolution: Second stage
The second phase of Einstein's "debate" with Bohr and the orthodox interpretation is characterized by an acceptance of the fact that it is, as a practical matter, impossible to simultaneously determine the values of certain incompatible quantities, but the rejection that this implies that these quantities do not actually have precise values. Einstein rejects the probabilistic interpretation of Born and insists that quantum probabilities are epistemic and not ontological in nature. As a consequence, the theory must be incomplete in some way. He recognizes the great value of the theory, but suggests that it "does not tell the whole story", and, while providing an appropriate description at a certain level, it gives no information on the more fundamental underlying level:
I have the greatest consideration for the goals which are pursued by the physicists of the latest generation which go under the name of quantum mechanics, and I believe that this theory represents a profound level of truth, but I also believe that the restriction to laws of a statistical nature will turn out to be transitory....Without doubt quantum mechanics has grasped an important fragment of the truth and will be a paragon for all future fundamental theories, for the fact that it must be deducible as a limiting case from such foundations, just as electrostatics is deducible from Maxwell's equations of the electromagnetic field or as thermodynamics is deducible from statistical mechanics.[citation needed]
These thoughts of Einstein would set off a line of research into hidden variable theories, such as the Bohm interpretation, in an attempt to complete the edifice of quantum theory. If quantum mechanics can be made complete in Einstein's sense, it cannot be done locally; this fact was demonstrated by John Stewart Bell with the formulation of Bell's inequality in 1964.
## Post-revolution: Third stage
Main article: Photon entanglement
### The argument of EPR
Title sections of historical papers on EPR.
In 1935 Einstein, Boris Podolsky and Nathan Rosen developed an argument, published in the magazine Physical Review with the title Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?, based on an entangled state of two systems. Before coming to this argument, it is necessary to formulate another hypothesis that comes out of Einstein's work in relativity: the principle of locality. The elements of physical reality which are objectively possessed cannot be influenced instantaneously at a distance.
The argument of EPR was in 1957 picked up by David Bohm and Yakir Aharonov in a paper published in Physical Review with the title Discussion of Experimental Proof for the Paradox of Einstein, Rosen, and Podolsky. The authors re-formulated the argument in terms of an entangled state of two particles, which can be summarized as follows:
1) Consider a system of two photons which at time t are located, respectively, in the spatially distant regions A and B and which are also in the entangled state of polarization $\left|\Psi\right\rang$ described below:
$\left|\Psi,t\right\rang = \frac1{\sqrt{2}}\left|1,V\right\rang \left|2,V\right\rang + \frac1{\sqrt{2}}\left|1,H\right\rang \left|2,H\right\rang.$
2) At time t the photon in region A is tested for vertical polarization. Suppose that the result of the measurement is that the photon passes through the filter. According to the reduction of the wave packet, the result is that, at time t + dt, the system becomes
$\left|\Psi,t+dt\right\rang = \left|1,V\right\rang \left|2,V\right\rang.$
3) At this point, the observer in A who carried out the first measurement on photon 1, without doing anything else that could disturb the system or the other photon ("assumption (R)", below), can predict with certainty that photon 2 will pass a test of vertical polarization. It follows that photon 2 possesses an element of physical reality: that of having a vertical polarization.
4) According to the assumption of locality, it cannot have been the action carried out in A which created this element of reality for photon 2. Therefore, we must conclude that the photon possessed the property of being able to pass the vertical polarization test before and independently of the measurement of photon 1.
5) At time t, the observer in A could have decided to carry out a test of polarization at 45°, obtaining a certain result, for example, that the photon passes the test. In that case, he could have concluded that photon 2 turned out to be polarized at 45°. Alternatively, if the photon did not pass the test, he could have concluded that photon 2 turned out to be polarized at 135°. Combining one of these alternatives with the conclusion reached in 4, it seems that photon 2, before the measurement took place, possessed both the property of being able to pass with certainty a test of vertical polarization and the property of being able to pass with certainty a test of polarization at either 45° or 135°. These properties are incompatible according to the formalism.
6) Since natural and obvious requirements have forced the conclusion that photon 2 simultaneously possesses incompatible properties, this means that, even if it is not possible to determine these properties simultaneously and with arbitrary precision, they are nevertheless possessed objectively by the system. But quantum mechanics denies this possibility and it is therefore an incomplete theory.
### Bohr's response
Bohr's response to this argument was published, five months later than the original publication of EPR, in the same magazine Physical Review and with exactly the same title as the original.[citation needed] The crucial point of Bohr's answer is distilled in a passage which he later had republished in Paul Arthur Schilpp's book Albert Einstein, scientist-philosopher in honor of the seventieth birthday of Einstein. Bohr attacks assumption (R) of EPR by stating:
The statement of the criterion in question is ambiguous with regard to the expression "without disturbing the system in any way". Naturally, in this case no mechanical disturbance of the system under examination can take place in the crucial stage of the process of measurement. But even in this stage there arises the essential problem of an influence on the precise conditions which define the possible types of prediction which regard the subsequent behaviour of the system...their arguments do not justify their conclusion that the quantum description turns out to be essentially incomplete...This description can be characterized as a rational use of the possibilities of an unambiguous interpretation of the process of measurement compatible with the finite and uncontrollable interaction between the object and the instrument of measurement in the context of quantum theory.
John Bell later argued that this passage is almost unintelligible.[citation needed] What does Bohr mean, Bell asks, by the specification "mechanical" that is used to refer to the "disturbances" that Bohr maintains should not be taken into consideration? What is meant by the expression "an influence on the precise conditions" if not that different measurements in A provide different information on the system in B? This fact is not only admitted but is an essential part of the argument of EPR. Lastly, what could Bohr have meant by the expression "uncontrollable interaction between the object and the measuring apparatus", considering that the central point of the argument of EPR is the hypothesis that, if one accepts locality, only the part of the system in A can be disturbed by the process of measurement and that, notwithstanding this fact, this process provides precise information on the part of the system in B? Is Bohr already contemplating the possibility of "spooky action at a distance"? If so, why not declare it explicitly? If one abandons the assumption of locality, the argument of EPR obviously collapses immediately.
The debates represent one of the highest points of scientific research in the first half of the twentieth century because it called attention to an element of quantum theory, quantum non-locality, which is absolutely central to our modern understanding of the physical world.
## Post-revolution: Fourth stage
In his last writing on the topic[citation needed], Einstein further refined his position, making it completely clear that what really disturbed him about the quantum theory was the problem of the total renunciation of all minimal standards of realism, even at the microscopic level, that the acceptance of the completeness of the theory implied. Although the majority of experts in the field agree that Einstein was wrong, the current understanding is still not complete (see Interpretation of quantum mechanics). There is no scientific consensus that determinism would have been refuted.[7][8]
## References
• Boniolo, G., (1997) Filosofia della Fisica, Mondadori, Milan.
• Bolles, Edmund Blair (2004) Einstein Defiant, Joseph Henry Press, Washington, D.C.
• Born, M. (1973) The Born Einstein Letters, Walker and Company, New York, 1971.
• Ghirardi, Giancarlo, (1997) Un'Occhiata alle Carte di Dio, Il Saggiatore, Milan.
• Pais, A., (1986) Subtle is the Lord... The Science and Life of Albert Einstein, Oxford University Press, Oxford, 1982.
• Shilpp, P.A., (1958) Albert Einstein: Philosopher-Scientist, Northwestern University and Southern Illinois University, Open Court, 1951.
1. ^ From Albert Einstein: Philosopher-Scientist (1949), publ. Cambridge University Press, 1949. Niels Bohr's report of conversations with Einstein.
2. ^ González AM. "Albert Einstein". Donostia International Physics Center. Retrieved 2010-08-30.
3. ^ a b Pais
4. ^ a b c Bolles
5. ^ (Einstein 1969). A reprint of this book was published by Edition Erbrich in 1982, ISBN 3-88682-005-X
6. ^ Momentum Transfer to a Free Floating Double Slit: Realization of a Thought Experiment from the Einstein-Bohr Debates, L. Ph. H. Schmidt et al. Physical Review Letters Week ending 2013
7. ^ Bishop, Robert C. (2011). "Chaos, Indeterminism, and Free Will". In Kane, Robert. The Oxford Handbook of Free Wil (Second ed.). Oxford, New York: Oxford University Press. p. 90. ISBN 978-0-19-539969-1. Retrieved 2013-02-04. "The key question is whether to understand the nature of this probability as epistemic or ontic. Along epistemic lines, one possibility is that there is some additional factor (i.e., a hidden mechanism) such that once we discover and understand this factor, we would be able to predict the observed behavior of the quantum stoplight with certainty (physicists call this approach a "hidden variable theory"; see, e.g., Bell 1987, 1-13, 29-39; Bohm 1952a, 1952b; Bohm and Hiley 1993; Bub 1997, 40-114, Holland 1993; see also the preceding essay in this volume by Hodgson). Or perhaps there is an interaction with the broader environment (e.g., neighboring buildings, trees) that we have not taken into account in our observations that explains how these probabilities arise (physicists call this approach decoherence or consistent histories15). Under either of these approaches, we would interpret the observed indeterminism in the behavior of stoplights as an expression of our ignorance about the actual workings. Under an ignorance interpretation, indeterminism would not be a fundamental feature of quantum stoplights, but merely epistemic in nature due to our lack of knowledge about the system. Quantum stoplights would turn to be deterministic after all."
8. ^ Baggott, Jim E. (2004). "Complementarity and Entanglement". Beyond Measure: Modern Physics, Philosophy, and the Meaning of Quantum Theory. Oxford, New York: Oxford University Press. p. 203. ISBN 0-19-852536-2. Retrieved 2013-02-04. "So, was Einstein wrong? In the sense that the EPR paper argued in favour of an objective reality for each quantum particle in an entangled pair independent of the other and of the measuring device, the answer must be yes. But if we take a wider view and ask instead if Einstein was wrong to hold to the realist's belief that the physics of the universe should be objective and deterministic, we must acknowledge that we cannot answer such a question. It is in the nature of theoretical science that there can be no such thing as certainty. A theory is only 'true' for as long as the majority of the scientific community maintain a consensus view that the theory is the one best able to explain the observations. And the story of quantum theory is not over yet." | 2014-08-30 21:02:51 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 19, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7193443179130554, "perplexity": 577.6725036980627}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-35/segments/1408500835699.86/warc/CC-MAIN-20140820021355-00097-ip-10-180-136-8.ec2.internal.warc.gz"} |
https://zbmath.org/serials/?q=se%3A00008132 | # zbMATH — the first resource for mathematics
## Mathematics
Short Title: Mathematics Publisher: Multidisciplinary Digital Publishing Institute (MDPI), Basel ISSN: 2227-7390/e Online: http://www.mdpi.com/journal/mathematics Comments: No longer indexed; Published electronic only as of Vol. 1 (2013). This journal is available open access.
Documents indexed: 467 Publications (2013–2018) References indexed: 466 Publications with 14,357 References
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http://mathoverflow.net/questions/127908/reduction-types-of-elliptic-curves/128617 | # reduction types of elliptic curves
Let $E/K$ be an elliptic curve, where $K$ is a complete local field with residue field $k$ and char$(k) = p$. I'm trying to make sense of Kodaira symbols and Tate's algorithm.
My current understanding is:
I$_0$ = good reduction
I$_n$ = multiplicative reduction with $\nu(j) = -n$.
I$_n^\ast$ = potential multiplicative reduction, eventually becoming I$_n$ in a field extension (so $\nu(j) = -n$).
I$_0^\ast$ = "non-exceptional" potential good reduction.
II, II$^\ast$, III, III$^\ast$, IV, IV$^\ast$ = "exceptional" potential good reduction. These can only happen when the $j$-invariant is equivalent to 0 or 1728 modulo $p$, or when $p = 2, 3$ (where everything is more complicated...)
Is this correct? Silverman's Advanced Topics in the Arithmetic of Elliptic Curves has a good table of reduction types when $k$ is algebraically closed, but I haven't been able to find something analogous for more general fields which gives me an overview of the possibilities. Also, why are Kodaira symbols named the way they are? For example, how are the reduction types II and II$^\ast$ related?
-
The formation of the Neron model over henselian discrete valuation rings commutes with scalar extension to the maximal unramified extension and its completion, so for any "table" of reduction types it is often sufficient to consider only separably closed residue fields. Hence, to the extent the residue field is perfect, it usually may as well be algebraically closed. (It isn't clear if Tate's algorithm works for imperfect residue field $k$ of char. 2 or 3, due to the existence of non-smooth regular Weierstrass cubics over such $k$.) For much more, read 10.2 in Qing Liu's textbook. – user28172 Apr 18 '13 at 5:45
What you said is almost correct.
First the list of types is complete if the residue field is algebraically closed. Over a perfect residue field, there are some more types, easy to handle (see nosr's comments). Essentially you identify irreducible components in the special fiber via possible automorphisms of the special fiber.
Over an imperfect residue field of characteristic 2 or 3 (see again nosr's comment), there are also some more types, decribed in Szydlo's thesis (J. Number Theory, 2004). See also JSE's answer at this question.
In residue characteristic 2, it is not true that type $I_n^*$ implies potentially multiplicative reduction, but the converse is true (potentially multiplicative reduction $I_m$ implies type $I_n^*$ for some $n$). There is a paper of Dino Lorenzini (in Pure Appli. Maths. Q., special issue in honor of Tate) where among other results, he gives the relation between $n$ and $m$ when the curve has potentially multiplicative reduction $I_n$. The relation involves the different of the minimal extension realizing the good reduction when $K$ is henseilan with algebraically closed $k$.
The relation between II and II$^{\star}$, when $p\ne 2, 3$, is that II is obtained by a quadratic twist of II$^\star$, similarly for IV and IV$^\star$ if I remember correctly. You can easily check on some examples using pari/gp. See Will's comments.
-
I believe this is incorrect. $II$ is a quadratic twist of $IV*$, and and $IV$ is a quadratic twist of $II*$. – Will Sawin Apr 24 '13 at 15:56
Thanks Will for the correction ! And III$^\star$ is a quadratic twist of III. – Qing Liu Apr 24 '13 at 17:11
$y^2=x^3-p$ has reduction type $II$, $y^2=x^3-1/p$ has reduction type $II^*$.
$y^2=x^3-p^2$ has reduction type $IV$, $y^2=x^3-1/p^2$ has reduction type $IV^*$.
Moreover, these examples are universal, in that everything of those fiber types looks like those equations up to linear change of variables and higher-order terms.
I believe this is the source of the names.
Similarly, $y^2=x^3-px$ is $III$, and $y^2=x^3-x/p$ is $III^*$.
This is only for $p\neq 2,3$.
-
Thanks Will! Could you point me towards a reference for those examples being universal? – stl Apr 28 '13 at 14:58
Unfortunately I don't have a reference. But the idea is simple - just put the elliptic curve in Weierstrass form $y^2=x^3-g_2x-g_3$. Then scale $g_2$ and $g_3$ so that one coefficient is as appropriate - I mean that if the fiber type is $II$, scale $g_3$ until it's $p$, but if it's $III^*$, scale $g_2$ until it's $1/p$. By Tate's algorthim, it's clear we can do this without changing the isomorphism class of the elliptic curve over the maximal unramified extension of $\mathbb Q_p$. – Will Sawin Apr 28 '13 at 20:09
Then the other one of $g_2$ and $g_3$ must make a higher-order contribution to the discriminant. This is what I mean by higher-order terms. This is easy to check from the $j$-invariant: If $g_2^3/(g_2^3-27g_3^2)$ is $0$ at $p$, then $g_2^3$ must vanish to higher order at $p$ than $g_3^2$. (Again, $p\neq 2,3$.) – Will Sawin Apr 28 '13 at 20:11
The naming comes from elliptic surfaces. http://en.wikipedia.org/wiki/Elliptic_surface
My recollection, III and III* are quadratic twists $v(\Delta)=3,9$,
as are II and IV* $v(\Delta)=2,8$ and are IV and II* $v(\Delta)=4,10$.
Note that $v(\Delta)=2,3,4$ for II,III,IV, and it goes up/down by 6 when twisting.
I think everything you have said is correct. The idea with "exceptional" good reduction, is that you acquire good reduction after a field extension, unlike [potentially] multiplicative case. The field to do this is easy for $p\ge 5$, but harder for primes above 2,3. See the paper of Kraus (in French, abstract in English). You can work locally, or also get a global field if wanted. | 2014-12-28 08:50:17 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.913237988948822, "perplexity": 527.9474626491875}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-52/segments/1419447556252.139/warc/CC-MAIN-20141224185916-00092-ip-10-231-17-201.ec2.internal.warc.gz"} |
https://codereview.stackexchange.com/questions/207120/upsert-query-using-cte-in-postgresql-9-4 | # Upsert query using CTE in PostgreSQL 9.4
I have a generic pipeline in SnapLogic that logs the start time of the executions of a group of incremental jobs. Suppose, the log table is as follows.
CREATE TABLE sl_control.interface_parameters_values (
interface_id varchar NOT NULL,
parameter_name varchar NOT NULL,
parameter_value varchar NULL
);
A few points to remember:
• There may or may not be an entry for a particular job (interface)
• This generic pipeline only updates the IncrementalTimestamp parameter of the interface. So, there will be only one entry to insert/update per interface.
• The individual values (for example, 'TEST0001', 'IncrementalTimestamp', 0) are being generated by a script and are being passed in batches of 150 to the query. So, VALUES part of the query will have at most 150 entries for each execution.
• Although I'm setting the batch as 150, the average number of interfaces I'm expecting is ~30.
Following is my upsert query:
WITH
/* write the new values */
v (
interface_id,
parameter_name,
parameter_value
) AS (
VALUES ('TEST0001', 'IncrementalTimestamp', 0),
('TEST0002', 'IncrementalTimestamp', 0),
('TEST0003', 'IncrementalTimestamp', 0),
('TEST0004', 'IncrementalTimestamp', 0),
('TEST0005', 'IncrementalTimestamp', 0)
),
/* update existing rows */
upsert AS (
UPDATE sl_control.interface_parameters_values ipv
SET
interface_id = v.interface_id,
parameter_name = v.parameter_name,
parameter_value = v.parameter_value
FROM v
WHERE (
ipv.interface_id = v.interface_id
AND ipv.parameter_name = v.parameter_name
)
RETURNING ipv.interface_id
)
/* insert missing rows */
INSERT INTO sl_control.interface_parameters_values (
interface_id,
parameter_name,
parameter_value
)
SELECT interface_id
, parameter_name
, parameter_value
FROM v
WHERE v.interface_id NOT IN (
SELECT interface_id FROM upsert
)
I had to take this approach because this particular PostgreSQL instance is version 9.4 and it does not support the ON CONFLICT syntax.
This query is working fine but is there any way this can be optimized further? Or is there any unseen pitfall to this approach. If this approach is good then I'll use this in one of our integration pipelines.
• Looks good to me. – 404 Dec 1 '18 at 13:48 | 2020-04-07 23:55:25 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.30717265605926514, "perplexity": 6652.701643177419}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-16/segments/1585371806302.78/warc/CC-MAIN-20200407214925-20200408005425-00439.warc.gz"} |
http://www.khronos.org/registry/vulkan/specs/1.1-extensions/man/html/vkCmdDispatch.html | ## C Specification
To record a dispatch, call:
void vkCmdDispatch(
VkCommandBuffer commandBuffer,
uint32_t groupCountX,
uint32_t groupCountY,
uint32_t groupCountZ);
## Parameters
• commandBuffer is the command buffer into which the command will be recorded.
• groupCountX is the number of local workgroups to dispatch in the X dimension.
• groupCountY is the number of local workgroups to dispatch in the Y dimension.
• groupCountZ is the number of local workgroups to dispatch in the Z dimension.
## Description
When the command is executed, a global workgroup consisting of groupCountX × groupCountY × groupCountZ local workgroups is assembled.
Valid Usage
• If a VkImageView is sampled with VK_FILTER_LINEAR as a result of this command, then the image view’s format features must contain VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_LINEAR_BIT
• If a VkImageView is accessed using atomic operations as a result of this command, then the image view’s format features must contain VK_FORMAT_FEATURE_STORAGE_IMAGE_ATOMIC_BIT
• If a VkImageView is sampled with VK_FILTER_CUBIC_EXT as a result of this command, then the image view’s format features must contain VK_FORMAT_FEATURE_SAMPLED_IMAGE_FILTER_CUBIC_BIT_EXT
• Any VkImageView being sampled with VK_FILTER_CUBIC_EXT as a result of this command must have a VkImageViewType and format that supports cubic filtering, as specified by VkFilterCubicImageViewImageFormatPropertiesEXT::filterCubic returned by vkGetPhysicalDeviceImageFormatProperties2
• Any VkImageView being sampled with VK_FILTER_CUBIC_EXT with a reduction mode of either VK_SAMPLER_REDUCTION_MODE_MIN_EXT or VK_SAMPLER_REDUCTION_MODE_MAX_EXT as a result of this command must have a VkImageViewType and format that supports cubic filtering together with minmax filtering, as specified by VkFilterCubicImageViewImageFormatPropertiesEXT::filterCubicMinmax returned by vkGetPhysicalDeviceImageFormatProperties2
• Any VkImage created with a VkImageCreateInfo::flags containing VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV sampled as a result of this command must only be sampled using a VkSamplerAddressMode of VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE.
• For each set n that is statically used by the VkPipeline bound to the pipeline bind point used by this command, a descriptor set must have been bound to n at the same pipeline bind point, with a VkPipelineLayout that is compatible for set n, with the VkPipelineLayout used to create the current VkPipeline, as described in [descriptorsets-compatibility]
• For each push constant that is statically used by the VkPipeline bound to the pipeline bind point used by this command, a push constant value must have been set for the same pipeline bind point, with a VkPipelineLayout that is compatible for push constants, with the VkPipelineLayout used to create the current VkPipeline, as described in [descriptorsets-compatibility]
• Descriptors in each bound descriptor set, specified via vkCmdBindDescriptorSets, must be valid if they are statically used by the VkPipeline bound to the pipeline bind point used by this command
• A valid pipeline must be bound to the pipeline bind point used by this command
• If the VkPipeline object bound to the pipeline bind point used by this command requires any dynamic state, that state must have been set for commandBuffer
• If the VkPipeline object bound to the pipeline bind point used by this command accesses a VkSampler object that uses unnormalized coordinates, that sampler must not be used to sample from any VkImage with a VkImageView of the type VK_IMAGE_VIEW_TYPE_3D, VK_IMAGE_VIEW_TYPE_CUBE, VK_IMAGE_VIEW_TYPE_1D_ARRAY, VK_IMAGE_VIEW_TYPE_2D_ARRAY or VK_IMAGE_VIEW_TYPE_CUBE_ARRAY, in any shader stage
• If the VkPipeline object bound to the pipeline bind point used by this command accesses a VkSampler object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V OpImageSample* or OpImageSparseSample* instructions with ImplicitLod, Dref or Proj in their name, in any shader stage
• If the VkPipeline object bound to the pipeline bind point used by this command accesses a VkSampler object that uses unnormalized coordinates, that sampler must not be used with any of the SPIR-V OpImageSample* or OpImageSparseSample* instructions that includes a LOD bias or any offset values, in any shader stage
• If the robust buffer access feature is not enabled, and if the VkPipeline object bound to the pipeline bind point used by this command accesses a uniform buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point
• If the robust buffer access feature is not enabled, and if the VkPipeline object bound to the pipeline bind point used by this command accesses a storage buffer, it must not access values outside of the range of the buffer as specified in the descriptor set bound to the same pipeline bind point
• If commandBuffer is an unprotected command buffer, any resource accessed by the VkPipeline object bound to the pipeline bind point used by this command must not be a protected resource
• If commandBuffer is a protected command buffer, any resource written to by the VkPipeline object bound to the pipeline bind point used by this command must not be an unprotected resource
• If commandBuffer is a protected command buffer, pipeline stages other than the framebuffer-space and compute stages in the VkPipeline object bound to the pipeline bind point must not write to any resource
• groupCountX must be less than or equal to VkPhysicalDeviceLimits::maxComputeWorkGroupCount[0]
• groupCountY must be less than or equal to VkPhysicalDeviceLimits::maxComputeWorkGroupCount[1]
• groupCountZ must be less than or equal to VkPhysicalDeviceLimits::maxComputeWorkGroupCount[2]
Valid Usage (Implicit)
• commandBuffer must be a valid VkCommandBuffer handle
• commandBuffer must be in the recording state
• The VkCommandPool that commandBuffer was allocated from must support compute operations
• This command must only be called outside of a render pass instance
Host Synchronization
• Host access to commandBuffer must be externally synchronized
• Host access to the VkCommandPool that commandBuffer was allocated from must be externally synchronized
Command Properties
Command Buffer Levels Render Pass Scope Supported Queue Types Pipeline Type
Primary
Secondary
Outside
Compute
Compute | 2019-10-14 07:12:54 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.2951130270957947, "perplexity": 5736.7439271168305}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-43/segments/1570986649232.14/warc/CC-MAIN-20191014052140-20191014075140-00169.warc.gz"} |
https://dev.royrags.com/post/2017-09-19/ | # Hugo Content Layout
Today I worked on another static site and learned more about Hugo’s content management organization.
Specifically, I learned much more about the distinction between sections, types, and taxonomies. These concepts are all related, and can all produce aggregate lists, but have very different degrees and mechanisms to configure.
sections are opinionated, unchangeable, attributes that are determined by where a file is placed. Seemingly the documentation indicates they are the top level directories under content, however there does appear to be some support for nested sections, including an open issue related to their documentation.
types are inferred from sections, but can also be specified in the frontmatter of a document. Types seem to be primarily intended to change the default metadata and visual presentation. They can also be used to filter a paginator in order to create a list page.
Finally, taxonomies allow relations between pieces of content. I did not realize that the support for tags was through taxonomies (as is categories be default).
All together that is a lot of ways to slice and dice and present your content, which can be pretty powerful. Also I have to give hugo lots of credit for making sane defaults and inferring things whenever possible without making it seem like too much magic. Additionally, the documentation is really good.
I did run into some interesting behavior related to _index.md pages, and how sections where inferred in nested directories, but did not keep enough notes to fully debug (also wasn’t sure the expected behavior prior to learning all this). Essentially a post in a nested sub folder under a top level section would be included in that section, but would not show up in the default paginator if an _index.md file was in it’s sub directory. Otherwise it would. I’ll leave you with that mystery (my hack resolution was to change the paginator to be based on type, I’ll have to think more on that).
## meta
I even passed up on my analog beeminder goal to make this post and hit a week long streak! Also I made all my goals public today! | 2019-04-25 11:54:56 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4327514171600342, "perplexity": 1748.1204412198758}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-18/segments/1555578721441.77/warc/CC-MAIN-20190425114058-20190425140058-00283.warc.gz"} |
http://www.mywordsolution.com/question/you-must-determine-the-natural-frequency-of-the/93539 | +1-415-315-9853
info@mywordsolution.com
## Engineering
Civil Engineering Chemical Engineering Electrical & Electronics Mechanical Engineering Computer Engineering Engineering Mathematics MATLAB Other Engineering Digital Electronics Biochemical & Biotechnology
Vibration of Electronics Module:
An electronics module is mounted on a machine and is modelled as a single degree-of freedom spring, mass, and damper. During normal operation, the module (of mass m kg) is subject to a harmonic force of F N at ω rad/s. The stiffness is k N/m and the natural damping in the system is c kg/s. The machine starts and stops during its normal operation, providing initial conditions to the module of x0= 0.01 m and v0 = 0.5 m/s. You must complete a numerical analysis and plot the displacement and velocity of the module as a function of time for the values assigned to you.
In addition, you must determine the natural frequency of the system and use this to produce a plot demonstrating the behavior of the module when resonance occurs.
Equation of Motion:
mx + cx + kx = Fo sinωt
Engineering Mathematics, Engineering
• Category:- Engineering Mathematics
• Reference No.:- M93539
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https://en.wikipedia.org/wiki/Feature_learning | # Feature learning
Diagram of the feature learning paradigm in machine learning for application to downstream tasks, which can be applied to either raw data such as images or text, or to an initial set of features for the data. Feature learning is intended to result in faster training or better performance in task-specific settings than if the data was inputted directly.[1]
In machine learning, feature learning or representation learning[2] is a set of techniques that allows a system to automatically discover the representations needed for feature detection or classification from raw data. This replaces manual feature engineering and allows a machine to both learn the features and use them to perform a specific task.
Feature learning is motivated by the fact that machine learning tasks such as classification often require input that is mathematically and computationally convenient to process. However, real-world data such as images, video, and sensor data has not yielded to attempts to algorithmically define specific features. An alternative is to discover such features or representations through examination, without relying on explicit algorithms.
Feature learning can be either supervised, unsupervised or self-supervised.
## Supervised
Supervised feature learning is learning features from labeled data. The data label allows the system to compute an error term, the degree to which the system fails to produce the label, which can then be used as feedback to correct the learning process (reduce/minimize the error). Approaches include:
### Supervised dictionary learning
Dictionary learning develops a set (dictionary) of representative elements from the input data such that each data point can be represented as a weighted sum of the representative elements. The dictionary elements and the weights may be found by minimizing the average representation error (over the input data), together with L1 regularization on the weights to enable sparsity (i.e., the representation of each data point has only a few nonzero weights).
Supervised dictionary learning exploits both the structure underlying the input data and the labels for optimizing the dictionary elements. For example, this[12] supervised dictionary learning technique applies dictionary learning on classification problems by jointly optimizing the dictionary elements, weights for representing data points, and parameters of the classifier based on the input data. In particular, a minimization problem is formulated, where the objective function consists of the classification error, the representation error, an L1 regularization on the representing weights for each data point (to enable sparse representation of data), and an L2 regularization on the parameters of the classifier.
### Neural networks
Neural networks are a family of learning algorithms that use a "network" consisting of multiple layers of inter-connected nodes. It is inspired by the animal nervous system, where the nodes are viewed as neurons and edges are viewed as synapses. Each edge has an associated weight, and the network defines computational rules for passing input data from the network's input layer to the output layer. A network function associated with a neural network characterizes the relationship between input and output layers, which is parameterized by the weights. With appropriately defined network functions, various learning tasks can be performed by minimizing a cost function over the network function (weights).
Multilayer neural networks can be used to perform feature learning, since they learn a representation of their input at the hidden layer(s) which is subsequently used for classification or regression at the output layer. The most popular network architecture of this type is Siamese networks.
## Unsupervised
Unsupervised feature learning is learning features from unlabeled data. The goal of unsupervised feature learning is often to discover low-dimensional features that capture some structure underlying the high-dimensional input data. When the feature learning is performed in an unsupervised way, it enables a form of semisupervised learning where features learned from an unlabeled dataset are then employed to improve performance in a supervised setting with labeled data.[13][14] Several approaches are introduced in the following.
### K-means clustering
K-means clustering is an approach for vector quantization. In particular, given a set of n vectors, k-means clustering groups them into k clusters (i.e., subsets) in such a way that each vector belongs to the cluster with the closest mean. The problem is computationally NP-hard, although suboptimal greedy algorithms have been developed.
K-means clustering can be used to group an unlabeled set of inputs into k clusters, and then use the centroids of these clusters to produce features. These features can be produced in several ways. The simplest is to add k binary features to each sample, where each feature j has value one iff the jth centroid learned by k-means is the closest to the sample under consideration.[6] It is also possible to use the distances to the clusters as features, perhaps after transforming them through a radial basis function (a technique that has been used to train RBF networks[15]). Coates and Ng note that certain variants of k-means behave similarly to sparse coding algorithms.[16]
In a comparative evaluation of unsupervised feature learning methods, Coates, Lee and Ng found that k-means clustering with an appropriate transformation outperforms the more recently invented auto-encoders and RBMs on an image classification task.[6] K-means also improves performance in the domain of NLP, specifically for named-entity recognition;[17] there, it competes with Brown clustering, as well as with distributed word representations (also known as neural word embeddings).[14]
### Principal component analysis
Principal component analysis (PCA) is often used for dimension reduction. Given an unlabeled set of n input data vectors, PCA generates p (which is much smaller than the dimension of the input data) right singular vectors corresponding to the p largest singular values of the data matrix, where the kth row of the data matrix is the kth input data vector shifted by the sample mean of the input (i.e., subtracting the sample mean from the data vector). Equivalently, these singular vectors are the eigenvectors corresponding to the p largest eigenvalues of the sample covariance matrix of the input vectors. These p singular vectors are the feature vectors learned from the input data, and they represent directions along which the data has the largest variations.
PCA is a linear feature learning approach since the p singular vectors are linear functions of the data matrix. The singular vectors can be generated via a simple algorithm with p iterations. In the ith iteration, the projection of the data matrix on the (i-1)th eigenvector is subtracted, and the ith singular vector is found as the right singular vector corresponding to the largest singular of the residual data matrix.
PCA has several limitations. First, it assumes that the directions with large variance are of most interest, which may not be the case. PCA only relies on orthogonal transformations of the original data, and it exploits only the first- and second-order moments of the data, which may not well characterize the data distribution. Furthermore, PCA can effectively reduce dimension only when the input data vectors are correlated (which results in a few dominant eigenvalues).
### Local linear embedding
Local linear embedding (LLE) is a nonlinear learning approach for generating low-dimensional neighbor-preserving representations from (unlabeled) high-dimension input. The approach was proposed by Roweis and Saul (2000).[18][19] The general idea of LLE is to reconstruct the original high-dimensional data using lower-dimensional points while maintaining some geometric properties of the neighborhoods in the original data set.
LLE consists of two major steps. The first step is for "neighbor-preserving", where each input data point Xi is reconstructed as a weighted sum of K nearest neighbor data points, and the optimal weights are found by minimizing the average squared reconstruction error (i.e., difference between an input point and its reconstruction) under the constraint that the weights associated with each point sum up to one. The second step is for "dimension reduction," by looking for vectors in a lower-dimensional space that minimizes the representation error using the optimized weights in the first step. Note that in the first step, the weights are optimized with fixed data, which can be solved as a least squares problem. In the second step, lower-dimensional points are optimized with fixed weights, which can be solved via sparse eigenvalue decomposition.
The reconstruction weights obtained in the first step capture the "intrinsic geometric properties" of a neighborhood in the input data.[19] It is assumed that original data lie on a smooth lower-dimensional manifold, and the "intrinsic geometric properties" captured by the weights of the original data are also expected to be on the manifold. This is why the same weights are used in the second step of LLE. Compared with PCA, LLE is more powerful in exploiting the underlying data structure.
### Independent component analysis
Independent component analysis (ICA) is a technique for forming a data representation using a weighted sum of independent non-Gaussian components.[20] The assumption of non-Gaussian is imposed since the weights cannot be uniquely determined when all the components follow Gaussian distribution.
### Unsupervised dictionary learning
Unsupervised dictionary learning does not utilize data labels and exploits the structure underlying the data for optimizing dictionary elements. An example of unsupervised dictionary learning is sparse coding, which aims to learn basis functions (dictionary elements) for data representation from unlabeled input data. Sparse coding can be applied to learn overcomplete dictionaries, where the number of dictionary elements is larger than the dimension of the input data.[21] Aharon et al. proposed algorithm K-SVD for learning a dictionary of elements that enables sparse representation.[22]
## Multilayer/deep architectures
The hierarchical architecture of the biological neural system inspires deep learning architectures for feature learning by stacking multiple layers of learning nodes.[23] These architectures are often designed based on the assumption of distributed representation: observed data is generated by the interactions of many different factors on multiple levels. In a deep learning architecture, the output of each intermediate layer can be viewed as a representation of the original input data. Each level uses the representation produced by previous level as input, and produces new representations as output, which is then fed to higher levels. The input at the bottom layer is raw data, and the output of the final layer is the final low-dimensional feature or representation.
### Restricted Boltzmann machine
Restricted Boltzmann machines (RBMs) are often used as a building block for multilayer learning architectures.[6][24] An RBM can be represented by an undirected bipartite graph consisting of a group of binary hidden variables, a group of visible variables, and edges connecting the hidden and visible nodes. It is a special case of the more general Boltzmann machines with the constraint of no intra-node connections. Each edge in an RBM is associated with a weight. The weights together with the connections define an energy function, based on which a joint distribution of visible and hidden nodes can be devised. Based on the topology of the RBM, the hidden (visible) variables are independent, conditioned on the visible (hidden) variables.[clarification needed] Such conditional independence facilitates computations.
An RBM can be viewed as a single layer architecture for unsupervised feature learning. In particular, the visible variables correspond to input data, and the hidden variables correspond to feature detectors. The weights can be trained by maximizing the probability of visible variables using Hinton's contrastive divergence (CD) algorithm.[24]
In general training RBM by solving the maximization problem tends to result in non-sparse representations. Sparse RBM[25] was proposed to enable sparse representations. The idea is to add a regularization term in the objective function of data likelihood, which penalizes the deviation of the expected hidden variables from a small constant ${\displaystyle p}$.
### Autoencoder
An autoencoder consisting of an encoder and a decoder is a paradigm for deep learning architectures. An example is provided by Hinton and Salakhutdinov[24] where the encoder uses raw data (e.g., image) as input and produces feature or representation as output and the decoder uses the extracted feature from the encoder as input and reconstructs the original input raw data as output. The encoder and decoder are constructed by stacking multiple layers of RBMs. The parameters involved in the architecture were originally trained in a greedy layer-by-layer manner: after one layer of feature detectors is learned, they are fed up as visible variables for training the corresponding RBM. Current approaches typically apply end-to-end training with stochastic gradient descent methods. Training can be repeated until some stopping criteria are satisfied.
## Self-supervised
Self-supervised representation learning is learning features by training on the structure of unlabeled data rather than relying on explicit labels for an information signal. This approach has enabled the combined use of deep neural network architectures and larger unlabeled datasets to produce deep feature representations.[9] Training tasks typically fall under the classes of either contrastive, generative or both.[26] Contrastive representation learning trains representations for associated data pairs, called positive samples, to be aligned, while pairs with no relation, called negative samples, are contrasted. A larger portion of negative samples is typically necessary in order to prevent catastrophic collapse, which is when all inputs are mapped to the same representation.[9] Generative representation learning tasks the model with producing the correct data to either match a restricted input or reconstruct the full input from a lower dimensional representation.[26]
A common setup for self-supervised representation learning of a certain data type (e.g. text, image, audio, video) is to pretrain the model using large datasets of general context, unlabeled data.[11] Depending on the context, the result of this is either a set of representations for common data segments (e.g. words) which new data can be broken into, or a neural network able to convert each new data point (e.g. image) into a set of lower dimensional features.[9] In either case, the output representations can then be used as an initialization in many different problem settings where labeled data may be limited. Specialization of the model to specific tasks is typically done with supervised learning, either by fine-tuning the model / representations with the labels as the signal, or freezing the representations and training an additional model which takes them as an input.[11]
Many self-supervised training schemes have been developed for use in representation learning of various modalities, often first showing successful application in text or image before being transferred to other data types.[9]
### Text
Word2vec is a word embedding technique which learns to represent words through self-supervision over each word and its neighboring words in a sliding window across a large corpus of text.[27] The model has two possible training schemes to produce word vector representations, one generative and one contrastive.[26] The first is word prediction given each of the neighboring words as an input.[27] The second is training on the representation similarity for neighboring words and representation dissimilarity for random pairs of words.[10] A limitation of word2vec is that only the pairwise co-occurrence structure of the data is used, and not the ordering or entire set of context words. More recent transformer-based representation learning approaches attempt to solve this with word prediction tasks.[9] GPT pretrains on next word prediction using prior input words as context,[28] whereas BERT masks random tokens in order to provide bidirectional context.[29]
Other self-supervised techniques extend word embeddings by finding representations for larger text structures such as sentences or paragraphs in the input data.[9] Doc2vec extends the generative training approach in word2vec by adding an additional input to the word prediction task based on the paragraph it is within, and is therefore intended to represent paragraph level context.[30]
### Image
The domain of image representation learning has employed many different self-supervised training techniques, including transformation,[31] inpainting,[32] patch discrimination[33] and clustering.[34]
Examples of generative approaches are Context Encoders, which trains an AlexNet CNN architecture to generate a removed image region given the masked image as input,[32] and iGPT, which applies the GPT-2 language model architecture to images by training on pixel prediction after reducing the image resolution.[35]
Many other self-supervised methods use siamese networks, which generate different views of the image through various augmentations that are then aligned to have similar representations. The challenge is avoiding collapsing solutions where the model encodes all images to the same representation.[36] SimCLR is a contrastive approach which uses negative examples in order to generate image representations with a ResNet CNN.[33] Bootstrap Your Own Latent (BYOL) removes the need for negative samples by encoding one of the views with a slow moving average of the model parameters as they are being modified during training.[37]
### Graph
The goal of many graph representation learning techniques is to produce an embedded representation of each node based on the overall network topology.[38] node2vec extends the word2vec training technique to nodes in a graph by using co-occurrence in random walks through the graph as the measure of association.[39] Another approach is to maximize mutual information, a measure of similarity, between the representations of associated structures within the graph.[9] An example is Deep Graph Infomax, which uses contrastive self-supervision based on mutual information between the representation of a “patch” around each node, and a summary representation of the entire graph. Negative samples are obtained by pairing the graph representation with either representations from another graph in a multigraph training setting, or corrupted patch representations in single graph training.[40]
### Video
With analogous results in masked prediction[41] and clustering,[42] video representation learning approaches are often similar to image techniques but must utilize the temporal sequence of video frames as an additional learned structure. Examples include VCP, which masks video clips and trains to choose the correct one given a set of clip options, and Xu et al., who train a 3D-CNN to identify the original order given a shuffled set of video clips.[43]
### Audio
Self-supervised representation techniques have also been applied to many audio data formats, particularly for speech processing.[9] Wav2vec 2.0 discretizes the audio waveform into timesteps via temporal convolutions, and then trains a transformer on masked prediction of random timesteps using a contrastive loss.[44] This is similar to the BERT language model, except as in many SSL approaches to video, the model chooses among a set of options rather than over the entire word vocabulary.[29][44]
### Multimodal
Self-supervised learning has also been used to develop joint representations of multiple data types.[9] Approaches usually rely on some natural or human-derived association between the modalities as an implicit label, for instance video clips of animals or objects with characteristic sounds,[45] or captions written to describe images.[46] CLIP produces a joint image-text representation space by training to align image and text encodings from a large dataset of image-caption pairs using a contrastive loss.[46] MERLOT Reserve trains a transformer-based encoder to jointly represent audio, subtitles and video frames from a large dataset of videos through 3 joint pretraining tasks: contrastive masked prediction of either audio or text segments given the video frames and surrounding audio and text context, along with contrastive alignment of video frames with their corresponding captions.[45]
Multimodal representation models are typically unable to assume direct correspondence of representations in the different modalities, since the precise alignment can often be noisy or ambiguous. For example, the text "dog" could be paired with many different pictures of dogs, and correspondingly a picture of a dog could be captioned with varying degrees of specificity. This limitation means that downstream tasks may require an additional generative mapping network between modalities to achieve optimal performance, such as in DALLE-2 for text to image generation.[47]
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https://www.impan.pl/pl/wydawnictwa/czasopisma-i-serie-wydawnicze/colloquium-mathematicum/all/137/1/87368/on-stable-equivalences-of-module-subcategories-over-a-semiperfect-noetherian-ring | JEDNOSTKA NAUKOWA KATEGORII A+
# Wydawnictwa / Czasopisma IMPAN / Colloquium Mathematicum / Wszystkie zeszyty
## On stable equivalences of module subcategories over a semiperfect noetherian ring
### Tom 137 / 2014
Colloquium Mathematicum 137 (2014), 7-26 MSC: Primary 16E05; Secondary 13C60. DOI: 10.4064/cm137-1-2
#### Streszczenie
Given a semiperfect two-sided noetherian ring $\varLambda$, we study two subcategories $\mathcal {A}_k(\varLambda )=\{M\in \mathrm {mod}\ \varLambda \mid \mathrm {Ext}_\varLambda ^j(\mathop {{\rm Tr}}M,\varLambda )=0\ (1\leq j\leq k)\}$ and $\mathcal {B}_k(\varLambda )=\{N\in \mathrm {mod}\ \varLambda \mid \mathrm {Ext}_\varLambda ^j(N,\varLambda )=0\ (1\leq j\leq k)\}$ of the category $\mathop {\rm mod} \varLambda$ of finitely generated right $\varLambda$-modules, where $\mathop {\rm Tr}M$ is Auslander's transpose of $M$. In particular, we give another convenient description of the categories $\mathcal {A}_{k}(\varLambda )$ and $\mathcal {B}_{k}(\varLambda )$, and we study category equivalences and stable equivalences between them. Several results proved in [J. Algebra 301 (2006), 748–780] are extended to the case when $\varLambda$ is a two-sided noetherian semiperfect ring.
#### Autorzy
of Science and Technology
Shinshu University
3-1-1 Asahi, Matsumoto
Nagano, 390-8621, Japan
e-mail
of Science and Technology
Shinshu University
3-1-1 Asahi, Matsumoto
Nagano, 390-8621, Japan
e-mail
• Kenji NishidaDepartment of Mathematical Sciences
Shinshu University
3-1-1 Asahi, Matsumoto
Nagano, 390-8621, Japan
e-mail
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Odśwież obrazek | 2022-12-02 07:12:47 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4439767003059387, "perplexity": 9604.680224393363}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710898.93/warc/CC-MAIN-20221202050510-20221202080510-00234.warc.gz"} |
https://www.aimsciences.org/article/doi/10.3934/cpaa.2022008?viewType=html | American Institute of Mathematical Sciences
doi: 10.3934/cpaa.2022008
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Monotonicity and symmetry of positive solutions to degenerate quasilinear elliptic systems in half-spaces and strips
1 Faculty of Economic Mathematics, University of Economics and Law, Ho Chi Minh City, Vietnam 2 Vietnam National University, Ho Chi Minh City, Vietnam 3 Faculty of Mathematics and Applications, Saigon University, 273 An Duong Vuong St., Ward 3, Dist. 5, Ho Chi Minh City, Vietnam
* Corresponding author
Received September 2021 Revised November 2021 Early access December 2021
By means of the method of moving planes, we study the monotonicity of positive solutions to degenerate quasilinear elliptic systems in half-spaces. We also prove the symmetry of positive solutions to the systems in strips by using similar arguments. Our work extends the main results obtained in [16,20] to the system, in which substantial differences with the single cases are presented.
Citation: Phuong Le, Hoang-Hung Vo. Monotonicity and symmetry of positive solutions to degenerate quasilinear elliptic systems in half-spaces and strips. Communications on Pure & Applied Analysis, doi: 10.3934/cpaa.2022008
References:
[1] A. D. Alexandrov, A characteristic property of spheres, Ann. Mat. Pura Appl., 58 (1962), 303-315. doi: 10.1007/BF02413056. Google Scholar [2] H. Berestycki, L. A. Caffarelli and L. Nirenberg, Monotonicity for elliptic equations in unbounded Lipschitz domains, Commun. Pure Appl. Math., 50 (1997), 1089-1111. doi: 10.1002/(SICI)1097-0312(199711)50:11<1089::AID-CPA2>3.0.CO;2-6. Google Scholar [3] H. Berestycki and L. Nirenberg, On the method of moving planes and the sliding method, Bol. Soc. Brasil. Mat. (N.S.), 22 (1991), 1-37. doi: 10.1007/BF01244896. Google Scholar [4] H. Berestycki, L. Caffarelli and L. Nirenberg, Further qualitative properties for elliptic equations in unbounded domains, Ann. Scuola Norm. Sup. Pisa Cl. Sci., 25 (1997), 69-94. Google Scholar [5] M. F. Bidaut-Véron, R. Borghol and L. Véron, Boundary Harnack inequality and a priori estimates of singular solutions of quasilinear elliptic equations, Calc. Var. Partial Differ Equ, 27 (2006), 159-177. doi: 10.1007/s00526-006-0003-7. Google Scholar [6] Z. Chen, C. S. Lin and W. Zou, Monotonicity and nonexistence results to cooperative systems in the half space, J. Funct. Anal., 266 (2014), 1088-1105. doi: 10.1016/j.jfa.2013.08.021. Google Scholar [7] L. Damascelli and F. Pacella, Monotonicity and symmetry of solutions of $p$-Laplace equations, $1 < p < 2$, via the moving plane method, Ann. Scuola Norm. Sup. Pisa Cl. Sci., 26 (1998), 689-707. Google Scholar [8] L. Damascelli and B. Sciunzi, Regularity, monotonicity and symmetry of positive solutions of $m$-Laplace equations, J. Differ. Equ., 206 (2004), 483-515. doi: 10.1016/j.jde.2004.05.012. Google Scholar [9] L. Damascelli and B. Sciunzi, Harnack inequalities, maximum and comparison principles, and regularity of positive solutions of $m$-Laplace equations, Calc. Var. Partial Differ. Equ., 25 (2006), 139-159. doi: 10.1007/s00526-005-0337-6. Google Scholar [10] E. N. Dancer, Moving plane methods for systems on half spaces, Math. Ann., 342 (2008), 245-254. doi: 10.1007/s00208-008-0226-3. Google Scholar [11] D. G. de Figueiredo, Monotonicity and symmetry of solutions of elliptic systems in general domains, NoDEA Nonlinear Differ. Equ. Appl., 1 (1994), 119-123. doi: 10.1007/BF01193947. Google Scholar [12] E. DiBenedetto, $C^{1+\alpha }$ local regularity of weak solutions of degenerate elliptic equations, Nonlinear Anal., 7 (1983), 827-850. doi: 10.1016/0362-546X(83)90061-5. Google Scholar [13] A. Farina, L. Montoro, G. Riey and B. Sciunzi, Monotonicity of solutions to quasilinear problems with a first-order term in half-spaces, Ann. Inst. H. Poincaré Anal. Non Linéaire, 32 (2015), 1-22. doi: 10.1016/j.anihpc.2013.09.005. Google Scholar [14] A. Farina, L. Montoro and B. Sciunzi, Monotonicity and one-dimensional symmetry for solutions of $-\Delta_pu = f(u)$ in half-spaces, Calc. Var. Partial Differ. Equ., 43 (2012), 123-145. doi: 10.1007/s00526-011-0405-z. Google Scholar [15] A. Farina, L. Montoro and B. Sciunzi, Monotonicity of solutions of quasilinear degenerate elliptic equation in half-spaces, Math. Ann., 357 (2013), 855-893. doi: 10.1007/s00208-013-0919-0. Google Scholar [16] A. Farina, L. Montoro and B. Sciunzi, Monotonicity in half-space of positive solutions to $-\Delta_pu = f(u)$ in the case $p>2$, Ann. Sc. Norm. Super. Pisa Cl. Sci., 17 (2017), 1207-1229. Google Scholar [17] A. Farina and E. Valdinoci, Flattening results for elliptic PDEs in unbounded domains with applications to overdetermined problems, Arch. Ration. Mech. Anal., 195 (2010), 1025-1058. doi: 10.1007/s00205-009-0227-8. Google Scholar [18] B. Gidas, W. M. Ni and L. Nirenberg, Symmetry and related properties via the maximum principle, Comm. Math. Phys., 68 (1979), 209-243. doi: 10.1007/BF01221125. Google Scholar [19] T. Kilpeläinen, H. Shahgholian and X. Zhong, Growth estimates through scaling for quasilinear partial differential equations, Ann. Acad. Sci. Fenn. Math., 32 (2007), 595-599. Google Scholar [20] L. Montoro, G. Riey and B. Sciunzi, Qualitative properties of positive solutions to systems of quasilinear elliptic equations, Adv. Differ. Equ., 20 (2015), 717-740. Google Scholar [21] P. Pucci and J. Serrin, The maximum principle, vol. 73 of Progress in Nonlinear Differential Equations and their Applications, Birkhäuser Verlag, Basel, 2007. Google Scholar [22] B. Sciunzi, Classification of positive $\mathcal{D}^{1, p}(\mathbb{R}^N)$-solutions to the critical $p$-Laplace equation in $\mathbb{R}^N$, Adv. Math., 291 (2016), 12-23. doi: 10.1016/j.aim.2015.12.028. Google Scholar [23] J. Serrin, A symmetry problem in potential theory, Arch. Rational Mech. Anal., 43 (1971), 304-318. doi: 10.1007/BF00250468. Google Scholar [24] P. Tolksdorf, Regularity for a more general class of quasilinear elliptic equations, J. Differ. Equ., 51 (1984), 126-150. doi: 10.1016/0022-0396(84)90105-0. Google Scholar [25] W. C. Troy, Symmetry properties in systems of semilinear elliptic equations, J. Differ. Equ., 42 (1981), 400-413. doi: 10.1016/0022-0396(81)90113-3. Google Scholar [26] J. Vétois, A priori estimates and application to the symmetry of solutions for critical $p$-Laplace equations, J. Differ. Equ., 260 (2016), 149-161. doi: 10.1016/j.jde.2015.08.041. Google Scholar
show all references
References:
[1] A. D. Alexandrov, A characteristic property of spheres, Ann. Mat. Pura Appl., 58 (1962), 303-315. doi: 10.1007/BF02413056. Google Scholar [2] H. Berestycki, L. A. Caffarelli and L. Nirenberg, Monotonicity for elliptic equations in unbounded Lipschitz domains, Commun. Pure Appl. Math., 50 (1997), 1089-1111. doi: 10.1002/(SICI)1097-0312(199711)50:11<1089::AID-CPA2>3.0.CO;2-6. Google Scholar [3] H. Berestycki and L. Nirenberg, On the method of moving planes and the sliding method, Bol. Soc. Brasil. Mat. (N.S.), 22 (1991), 1-37. doi: 10.1007/BF01244896. Google Scholar [4] H. Berestycki, L. Caffarelli and L. Nirenberg, Further qualitative properties for elliptic equations in unbounded domains, Ann. Scuola Norm. Sup. Pisa Cl. Sci., 25 (1997), 69-94. Google Scholar [5] M. F. Bidaut-Véron, R. Borghol and L. Véron, Boundary Harnack inequality and a priori estimates of singular solutions of quasilinear elliptic equations, Calc. Var. Partial Differ Equ, 27 (2006), 159-177. doi: 10.1007/s00526-006-0003-7. Google Scholar [6] Z. Chen, C. S. Lin and W. Zou, Monotonicity and nonexistence results to cooperative systems in the half space, J. Funct. Anal., 266 (2014), 1088-1105. doi: 10.1016/j.jfa.2013.08.021. Google Scholar [7] L. Damascelli and F. Pacella, Monotonicity and symmetry of solutions of $p$-Laplace equations, $1 < p < 2$, via the moving plane method, Ann. Scuola Norm. Sup. Pisa Cl. Sci., 26 (1998), 689-707. Google Scholar [8] L. Damascelli and B. Sciunzi, Regularity, monotonicity and symmetry of positive solutions of $m$-Laplace equations, J. Differ. Equ., 206 (2004), 483-515. doi: 10.1016/j.jde.2004.05.012. Google Scholar [9] L. Damascelli and B. Sciunzi, Harnack inequalities, maximum and comparison principles, and regularity of positive solutions of $m$-Laplace equations, Calc. Var. Partial Differ. Equ., 25 (2006), 139-159. doi: 10.1007/s00526-005-0337-6. Google Scholar [10] E. N. Dancer, Moving plane methods for systems on half spaces, Math. Ann., 342 (2008), 245-254. doi: 10.1007/s00208-008-0226-3. Google Scholar [11] D. G. de Figueiredo, Monotonicity and symmetry of solutions of elliptic systems in general domains, NoDEA Nonlinear Differ. Equ. Appl., 1 (1994), 119-123. doi: 10.1007/BF01193947. Google Scholar [12] E. DiBenedetto, $C^{1+\alpha }$ local regularity of weak solutions of degenerate elliptic equations, Nonlinear Anal., 7 (1983), 827-850. doi: 10.1016/0362-546X(83)90061-5. Google Scholar [13] A. Farina, L. Montoro, G. Riey and B. Sciunzi, Monotonicity of solutions to quasilinear problems with a first-order term in half-spaces, Ann. Inst. H. Poincaré Anal. Non Linéaire, 32 (2015), 1-22. doi: 10.1016/j.anihpc.2013.09.005. Google Scholar [14] A. Farina, L. Montoro and B. Sciunzi, Monotonicity and one-dimensional symmetry for solutions of $-\Delta_pu = f(u)$ in half-spaces, Calc. Var. Partial Differ. Equ., 43 (2012), 123-145. doi: 10.1007/s00526-011-0405-z. Google Scholar [15] A. Farina, L. Montoro and B. Sciunzi, Monotonicity of solutions of quasilinear degenerate elliptic equation in half-spaces, Math. Ann., 357 (2013), 855-893. doi: 10.1007/s00208-013-0919-0. Google Scholar [16] A. Farina, L. Montoro and B. Sciunzi, Monotonicity in half-space of positive solutions to $-\Delta_pu = f(u)$ in the case $p>2$, Ann. Sc. Norm. Super. Pisa Cl. Sci., 17 (2017), 1207-1229. Google Scholar [17] A. Farina and E. Valdinoci, Flattening results for elliptic PDEs in unbounded domains with applications to overdetermined problems, Arch. Ration. Mech. Anal., 195 (2010), 1025-1058. doi: 10.1007/s00205-009-0227-8. Google Scholar [18] B. Gidas, W. M. Ni and L. Nirenberg, Symmetry and related properties via the maximum principle, Comm. Math. Phys., 68 (1979), 209-243. doi: 10.1007/BF01221125. Google Scholar [19] T. Kilpeläinen, H. Shahgholian and X. Zhong, Growth estimates through scaling for quasilinear partial differential equations, Ann. Acad. Sci. Fenn. Math., 32 (2007), 595-599. Google Scholar [20] L. Montoro, G. Riey and B. Sciunzi, Qualitative properties of positive solutions to systems of quasilinear elliptic equations, Adv. Differ. Equ., 20 (2015), 717-740. Google Scholar [21] P. Pucci and J. Serrin, The maximum principle, vol. 73 of Progress in Nonlinear Differential Equations and their Applications, Birkhäuser Verlag, Basel, 2007. Google Scholar [22] B. Sciunzi, Classification of positive $\mathcal{D}^{1, p}(\mathbb{R}^N)$-solutions to the critical $p$-Laplace equation in $\mathbb{R}^N$, Adv. Math., 291 (2016), 12-23. doi: 10.1016/j.aim.2015.12.028. Google Scholar [23] J. Serrin, A symmetry problem in potential theory, Arch. Rational Mech. Anal., 43 (1971), 304-318. doi: 10.1007/BF00250468. Google Scholar [24] P. Tolksdorf, Regularity for a more general class of quasilinear elliptic equations, J. Differ. Equ., 51 (1984), 126-150. doi: 10.1016/0022-0396(84)90105-0. Google Scholar [25] W. C. Troy, Symmetry properties in systems of semilinear elliptic equations, J. Differ. Equ., 42 (1981), 400-413. doi: 10.1016/0022-0396(81)90113-3. Google Scholar [26] J. Vétois, A priori estimates and application to the symmetry of solutions for critical $p$-Laplace equations, J. Differ. Equ., 260 (2016), 149-161. doi: 10.1016/j.jde.2015.08.041. Google Scholar
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Article outline | 2022-01-24 14:25:51 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7058236598968506, "perplexity": 4117.947606171431}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320304570.90/warc/CC-MAIN-20220124124654-20220124154654-00690.warc.gz"} |
https://enacademic.com/dic.nsf/enwiki/6649058/Equilibrium_fractionation | # Equilibrium fractionation
Equilibrium isotope fractionation is the partial separation of isotopes between two or more substances in chemical equilibrium. Equilibrium fractionation is strongest at low temperatures, and (along with kinetic isotope effects) forms the basis of the most widely used isotopic paleothermometers (or climate proxies): D/H and 18O/16O records from ice cores, and 18O/16O records from calcium carbonate. It is thus important for the construction of geologic temperature records. Isotopic fractionations attributed to equilibrium processes have been observed in many elements, from hydrogen (D/H) to uranium (238U/235U). In general, the light elements (especially hydrogen, boron, carbon, nitrogen, oxygen and sulfur) are most susceptible to fractionation, and their isotopes tend to be separated to a greater degree than heavier elements.
Most equilibrium fractionations are thought to result from the reduction in vibrational energy (especially zero-point energy) when a more massive isotope is substituted for a less massive one. This leads to higher concentrations of the massive isotopes in substances where the vibrational energy is most sensitive to isotope substitution, i.e., those with the highest bond force constants.
In a reaction involving the exchange of two isotopes, lX and hX, of element “X” in molecules AX and BX,
:$A^lX + B^hX leftrightarrow A^hX + B^lX$
each reactant molecule is identical to a product except for the distribution of isotopes (i.e., they are isotopologues). The amount of isotopic fractionation in an exchange reaction can be expressed as a fractionation factor:
:$alpha = frac\left\{\left(^hX/^lX\right)_\left\{AX\left\{\left(^hX/^lX\right)_\left\{BX$
$alpha = 1$ indicates that the isotopes are distributed evenly between AX and BX, with no isotopic fractionation. $alpha > 1$ indicates that hX is concentrated in substance AX, and $alpha < 1$ indicates hX is concentrated in substance BX. $alpha$ is closely related to the equilibrium constant (Keq):
:$alpha = \left(K_\left\{eq\right\} cdot Pi sigma_\left\{Products\right\}/ Pi sigma_\left\{Reactants\right\}\right)^\left\{1/n\right\}$
where $Pisigma_\left\{Products\right\}$ is the product of the rotational symmetry numbers of the products (right side of the exchange reaction), $Pisigma_\left\{Reactants\right\}$ is the product of the rotational symmetry numbers of the reactants (left side of the exchange reaction), and $n$ is the number of atoms exchanged.
An example of equilibrium isotope fractionation is the concentration of heavy isotopes of oxygen in liquid water, relative to water vapor,
:$H_2^\left\{16\right\}O_\left\{\left(l\right)\right\} + H_2^\left\{18\right\}O_\left\{\left(g\right)\right\} leftrightarrow H_2^\left\{18\right\}O_\left\{\left(l\right)\right\} + H_2^\left\{16\right\}O_\left\{\left(g\right)\right\}$
At 20oC, the equilibrium fractionation factor for this reaction is
:$alpha = frac\left\{\left(^\left\{18\right\}O/^\left\{16\right\}O\right)_\left\{Liquid\left\{\left(^\left\{18\right\}O/^\left\{16\right\}O\right)_\left\{Vapor = 1.0098$
Equilibrium fractionation is a type of mass-dependent isotope fractionation, while mass-independent fractionation is usually assumed to be a non-equilibrium process.
ee also
Stable isotope
Isotope geochemistry
Kinetic isotope effect
Isotope analysis
δ18O
Kinetic fractionation
Mass-independent fractionation
References
Chacko T., Cole D.R., and Horita J. (2001) Equilibrium oxygen, hydrogen and carbon isotope fractionation factors applicable to geologic systems. Reviews in Mineralogy and Geochemistry, v. 43, p. 1-81.
Horita J. and Wesolowski D.J. (1994) Liquid-vapor fractionation of oxygen and hydrogen isotopes of water from the freezing to the critical temperature. Geochimica et Cosmochimica Acta, v. 58, p. 3425-2437.
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### Look at other dictionaries:
• isotopic fractionation — ▪ chemistry enrichment of one isotope relative to another in a chemical or physical process. Two isotopes of an element are different in weight but not in gross chemical properties, which are determined by the number of electrons. However,… … Universalium
• Mass-independent fractionation — Mass independent (isotope) fractionation refers to any chemical or physical process that acts to separate isotopes, where the amount of separation does not scale in proportion with the difference in the masses of the isotopes. Most isotopic… … Wikipedia
• Kinetic fractionation — is a process that separates stable isotopes from each other by their mass during unidirectional processes.One naturally occurring example of kinetic fractionation is the evaporation of seawater to form clouds. In this instance, isotopically… … Wikipedia
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• separation and purification — ▪ chemistry Introduction in chemistry, separation of a substance into its components and the removal of impurities. There are a large number of important applications in fields such as medicine and manufacturing. General principles… … Universalium
• rare-earth element — /rair errth /, Chem. any of a group of closely related metallic elements, comprising the lanthanides, scandium, and yttrium, that are chemically similar by virtue of having the same number of valence electrons. Also called rare earth metal. [1955 … Universalium | 2020-10-26 22:08:52 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 12, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6974852085113525, "perplexity": 4058.58175252132}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107892062.70/warc/CC-MAIN-20201026204531-20201026234531-00379.warc.gz"} |
https://www.gamedev.net/blogs/entry/2259005-breaking-down-the-epoch-parser/ | • entries
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# Breaking down the Epoch parser
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I've had several requests for a detailed look at how the Epoch compiler parser works, so I figured I'd write up a summary of how everything fits together.
All Epoch programs begin their life in the entrypoint function. The compiler's entrypoint is fairly simple, but it contains a lot of extra stuff related to parsing the command line, opening files, and so on; we'll skip those details as they're fairly boring.
The relevant bit is a call to the function Parse, which is passed in a string containing the source code, and the length of that string. So let's look at Parse!
Parse : string code, integer len -> boolean success = false{ Lex(code, len) // Discard the dummy token PopToken() IREnterProgram() string token = PeekToken(0) while(token != "") { if(ParseGlobalBlock()) { } elseif(ParseSumType()) { } elseif(ParseWeakAlias()) { } elseif(ParseStrongAlias()) { } elseif(ParseStructure()) { } elseif(!ParseFunction()) { print("Error: code could not be parsed: " ; token ; " " ; PeekToken(1) ; " " ; PeekToken(2)) return() } token = PeekToken(0) } IRExitProgram() success = true}
The first thing we do is call Lex to perform lexical analysis on the input. I'll ignore lexing for now; what's interesting about this function is its general shape, as seen inside the while loop.
Epoch's current compiler uses a fairly rudimentary recursive descent parser. Instead of fancier techniques involving parser generators, grammars, and other trappings of academic parser work, it's just a hand-written set of functions that divide and conquer the input until everything is consumed.
The while loop in the Parse function is a pretty standard driver for such a parser. As you can see, all it does is repeatedly call other functions, and if all of those calls return false, it will barf an error message. Note that error handling is basically non-existent in Epoch's compiler right now, and building out a good diagnostic system would make the code considerably lengthier.
One important thing to note about this loop is that the order in which functions are called is actually important. There are places in the Epoch grammar where very similar sequences of tokens might mean very different things in the code; the order in which we try to match the input token stream is critical to making sure we pick the right variation. In general, more specific forms should precede more general forms.
This function only really shows one major example, which is resolving conflicts between algebraic sum type definitions and strong alias definitions. In Epoch, we can write the following code:
type Example : integer | stringtype Demo : integer
The first one is an algebraic sum type definition, and the second is a strong alias. The first basically means "anything of Example type can contain either an integer or a string, but not both at the same time." The second means "anything of Demo type acts like an integer but cannot be mixed with anything else that is integer-typed."
The parser needs to check for the more specific form first, i.e. sum types. If we checked for the more generic form first, i.e. strong aliases, we would create a problem: we could never correctly parse sum type definitions! This is because the general form would consume the tokens for the first half of the sum type definition, look at them, see that they are a legal strong alias, and then continue forward. But the next thing it would encounter would be half of a sum type definition, and it wouldn't know what to do with that.
So now we have some basic structure and ground rules for writing our parser. How does the rest work?
Essentially, it's all more of the same! Recursive descent has the nice property that almost all the code looks very similar, and it's easy to deduce what things are going on once you're used to the patterns. It's also easier to make very intelligent error messages, because you can inject hand-written code for every possible parsing scenario. Unfortunately I don't have any great examples of error diagnostics in the current code, so you'll have to use your imagination.
To see a concrete example, let's look at the code that handles strong type aliases:
ParseStrongAlias : -> boolean matched = false{ if(!PeekWithExpectation(0, "type")) { return() } if(!PeekWithExpectation(2, ":")) { return() } PopToken() string aliasname = PeekToken(0) string basename = PeekToken(2) PopTokens(3) OnCodeGenRegisterAlias((++GlobalAliasCounter), PoolString(aliasname), PoolString(basename)) matched = true}
This is pretty short and sweet. Note that the default return value of the function is false, meaning that it didn't find a match for what it was looking for.
The first thing we do is look for the token "type", since all strong aliases begin with that keyword. If that keyword isn't the current token, we are obviously not looking at a valid strong alias, so we can abort parsing and let someone else try and match.
Secondly, we look for the colon which is required to appear after the name of the type being defined (see above for an example of a strong alias definition). Simple enough.
Once that's done, we throw away a token (which we know has to be the "type" keyword). Then we store off two tokens: one for the type's name, and one for the type's base. Then we consume three tokens (remember the colon that appears in there!). Lastly, we call some external code that isn't part of the parser. This code is what rigs up the type alias in the program's AST, so that the alias can be used as part of type-checking the program later on in the compilation process.
And that's really about it. The entire parser is just a handful of these functions, that break down the grammatical rules of the language into smaller and smaller nested parts. So let's run through a simple Epoch program and see what parses what! (You can follow along here if you like.)
entrypoint :{ print("Hello world!")}
We start life in the Parse function, as above. We then repeatedly try to parse each of the code constructs that are allowed to live at the top level of a file. Think of it as asking a question for each function call.
Is it a global block? No.
Is it a sum type definition? No.
Is it a weak alias definition? No.
Is it a strong alias definition? No.
Is it a structure definition? No.
Is it a function?
Aha! Finally we get somewhere! This looks like a function. So let's walk into the ParseFunction() code and see what happens next:
Does it have parameters? No.
Does it have a return value? No.
Does it have any tags? No.
Does it have a code body?
Yes! So let's parse a code block! Now we're in the ParseCodeBlock() function.
ParseCodeBlock is similar to Parse in that it contains a while loop; it will continue parsing until it finds the } that ends the current code block.
Is it a control entity, such as an if statement or while loop? No.
Is it a preincrement/decrement statement? No.
Is it a postincrement/decrement statement? No.
Is it a regular statement, i.e. a function call? Yes!
And therefore we can skip checking if it is a variable initialization or assignment.
ParseStatement() is where we are now. Ignoring some unrelated complexity for templates and whatnot, this is basically the same pattern yet again: a while loop, parsing until we reach the closing ) that represents the end of the function call.
Is it a valid expression? Yes!
So let's move on to ParseExpression(). This one gets a bit hairy, so let's ignore the details and just focus on the general principle: ParseExpression finds "Hello world!" as a string literal, and knows that this is the parameter to the function we're trying to call.
In this case, the function we're calling is print. So we pair up the function name with its parameters, hand those off to the AST construction logic, and wander back up the call stack.
We return from ParseStatement() and return to ParseCodeBlock(). There's only one statement, so ParseCodeBlock() returns. There's the end of the function, so ParseFunction() returns. There's no more code to look at, so Parse() returns.
And there you have it!
## 1 Comment
Thanks, Apoch!
You even went the"extra-mile".
## Create an account
Register a new account | 2018-06-24 05:58:44 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4690588116645813, "perplexity": 1681.9383249603857}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267866358.52/warc/CC-MAIN-20180624044127-20180624064127-00052.warc.gz"} |
https://www.physicsforums.com/threads/double-integral.114422/ | # Homework Help: Double integral
1. Mar 15, 2006
### thenewbosco
Perhaps someone can explain how to do, or a trick to solve this integral:
$$\int_{0}^{3}\int_{\sqrt{y+1}}^{2} \frac{e^x}{x+1}$$ dx dy
i dont know if $$\frac{e^x}{x+1}$$ has an elementary antideriv. so there should be some trick to solving this i guess....
Last edited: Mar 15, 2006
2. Mar 15, 2006
### Hurkyl
Staff Emeritus
You have to use '_' and '^' to set the limits on an integral. e.g.
\int_{lower}^{upper}
And you forgot to put your dx's and dy's in the problem.
The first thing I think of when I'm stumped on a double integral is to reverse the order of integration to see if that helps. Have you tried that?
Last edited: Mar 15, 2006
3. Mar 15, 2006
### thenewbosco
right there it is correctly formatted. but by reversing the order, you will have a y in the final answer, not like it helps to reverse in this case anyways
4. Mar 15, 2006
### Hurkyl
Staff Emeritus
Well, when you reverse the order, the limits change, right? You won't know if it helps until you try it!
5. Mar 15, 2006
### buzzmath
use integration by parts.
Last edited: Mar 15, 2006
6. Mar 15, 2006
### thenewbosco
what do you choose for u and dv? i cannot simplify it?
7. Mar 15, 2006
### buzzmath
try using u = x+l and dv=e^xdx then du=dx and v=e^x
do you know the formula for integration by parts?
8. Mar 15, 2006
### shmoe
Have you, thenewbosco, followed this advice yet?
9. Mar 15, 2006
### thenewbosco
if you try this you get 3*e^x/(x+1) which doesnt really help any?
10. Mar 15, 2006
### shmoe
When you change the order of integration, you have to be careful with the limits. It might help if you sketch the region you are integrating over. What is the integral after you change the order?
11. Mar 16, 2006
### HallsofIvy
Since the problem is
$$\int \frac{e^x dx}{x+1}$$
rather than
$$\int (x+1)e^x dx$$
that doesn't help at all.
Changing the order of integration is the way to go.
Thenewbosco, have you sketched the area over which you are integrating? That's the best way to find the new limits of integration. Once you've done that you can use buzzmath's suggestion of integration by parts but with u= x-1, not x+1! | 2018-08-18 02:58:22 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7592031955718994, "perplexity": 2031.7940897816134}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-34/segments/1534221213264.47/warc/CC-MAIN-20180818021014-20180818041014-00665.warc.gz"} |
https://www.gamedev.net/forums/topic/491883-distortion-of-queried-virtual-shadow-maps/ | # Distortion of Queried Virtual Shadow Maps
This topic is 3709 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.
## Recommended Posts
I have implemented the QVSM in C++ and DirectX. Now I have a question about resolution. PrintScreenWithArrow.png is my result of QVSM. But the place in the arrow has distortion or break in the edge if you zoom in to see. My situation is SM Size=1024x1024 the sm tile in axis=2x2 If I use the sm size of 2048x2048 and the sm tile in axis of 1x1, the distortion will not appear. So I think that is the problem in My Code of ShadowShadowResultTexureWithSmTilShadowMap(in attached file of ShadowShadowResultTexureWithSmTilShadowMap.txt) and technique TShadowQVSM_ADPATIVE3(in attached file of adaptive.txt)
{
pass p0
{
ZWriteEnable=FALSE;//RenderState.ZBufferEnable = true;
ZEnable=FALSE;//RenderState.ZBufferWriteEnable = true;
}
}
Could somebody have the same problem in your program? Or Could somebody help me to see my code and point the problem and error? PS:Attached File I put in the web: http://cid-fbeb6373d9321a7f.skydrive.live.com/self.aspx/%e5%85%ac%e9%96%8b/questions/20080423.rar
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× | 2018-06-19 22:27:44 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.20373378694057465, "perplexity": 3546.1117842215253}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-26/segments/1529267863206.9/warc/CC-MAIN-20180619212507-20180619232507-00406.warc.gz"} |
https://physics.stackexchange.com/questions/300939/why-cant-the-klein-gordon-equation-explain-the-hydrogen-atom-but-the-dirac-equa/301247 | # Why can't the Klein-Gordon equation explain the hydrogen atom but the Dirac equation does?
Why can't the Klein-Gordon equation with a Couloumb potential describe the hydrogen atom?
Why can the first order Dirac equation explain it? What are the failures?
• ...because it fails to take into account the electron's spin, the equation predicts the hydrogen atom's fine structure incorrectly, including overestimating the ... : Klein–Gordon equation – Frobenius Dec 25 '16 at 20:14
Electrons are spin-1/2 particles (this qualifies them as fermions, but is not immediately relevant for this discussion).
KG equation is for spin-0 particles, whereas Dirac equation is for spin-1/2 particles. Therefore the proper equation to describe an electron is the latter.
Note that, however, the low-energy limit of both of them gives back Schrödinger equation, therefore in this approximation you can put the spin "by hand" and long as you need it, and this works both for fermions and for bosons.
• Also the field operator for electrons also obeys the Klein Gordon equation. It will give some informations on it but not all. – Slereah Dec 27 '16 at 9:03
• It obeys KG equation (or better, it satisfies the mass-shell condition $P^2\psi=m^2\psi$) as you can see by taking the "square" of Dirac's differential operator, but the latter has a much richer structure due to the fact that it carries spin. – yoric Dec 27 '16 at 9:06
The reason is electron spin. The energy of the Dirac and Klein-Gordon solution differ precisely by the substitution l<->j. The Klein-Gordon equation needs to be extended with a term describing the interaction of electron spin with the nuclear potential. The resulting equation is known as the squared Dirac equation. See Itzykson and Zuber, Ch. 2.3, for a solution of the Dirac equation for the single electron case via the squared Dirac equation.
The application of the Klein-Gordon equation for the hydrogen atom leads to logical contradictions. Allowance for relativism in the Klein-Gordon equation should lead to more accurate solutions for the hydrogen atom compared with the Schrodinger equation. However, on the contrary, solutions became increasingly worse with an increase in the nuclear charge. Finally, for the element Z = 69 the solution of the Klein-Gordon equation terminates. The Klein-Gordon equation has other drawbacks. Therefore, we can say that the Klein-Gordon equation is erroneous.
• Note that the naive Dirac equation also has no solution for the $S$ state when $Z$ becomes large enough. – WAH Feb 9 '18 at 15:14
• The Dirac equation has solutions up to Z = 137. – Mareta Arakelyan Feb 9 '18 at 17:46
• Are you sure? All the hydrogen derivations I've seen for the Dirac equation have imaginary energies for $S$ states once $Z\alpha=1/2$. See, for example, quantummechanics.ucsd.edu/ph130a/130_notes/node501.html or physics.sharif.edu/~qmech/puppel.pdf. – WAH Feb 10 '18 at 6:41
• I'm not sure which formula you mean. I ask you to give a formula for calculating the energy of the ground state. And an example of calculating where the imaginary energy is obtained. – Mareta Arakelyan Feb 10 '18 at 15:24 | 2019-07-18 21:32:17 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8816452026367188, "perplexity": 415.7389191705382}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-30/segments/1563195525829.33/warc/CC-MAIN-20190718211312-20190718233312-00249.warc.gz"} |
http://pacsan.com/gnel9/xef2-dipole-moment-bb0b8c | # xef2 dipole moment
Dip ole moment is measured in Debye units, which is equal to the distance between the charges multiplied by the charge (1 Debye eq uals $$3.34 \times 10^{-30}\; C\, m$$). In the molecule XeF2, how many pairs of electrons surround Xe and what is the molecular geometry? NF3. Click hereto get an answer to your question ️ Number of molecules having non - zero dipole moment. Follow ChemTube3D on Kudos Both Xe-F atoms have equal dipole moment but in the opposite direction of each other due to which the net dipole moment of the entire molecule … Chlorine trifluoride has three polarized bonds and they combine to produce a small molecular dipole along the Cl-F bond. No votes so far! Jmol.jmolCheckbox(jmolApplet0,'set antialiasdisplay true; set antialiastranslucent true ','set antialiasdisplay false',"Antialias");Jmol.jmolButton(jmolApplet0,"draw pointgroup;","Show All Symmetry Elements"); Home / Structure and Bonding / Dipoles and Electrostatic surfaces / Dipoles and Electrostatic Surfaces XeF4, ClF3 and CCl3Br, Use the buttons to display the dipoles, charges and electrostatic potential mapped onto the surface of each molecule. A. CH4 B. CCl4 C. CO2 D. SO2 E. none of these. Thirty are in lone pairs with F atoms. Get 1:1 help now from expert Chemistry tutors Jmol.jmolCheckbox(jmolApplet0,"spin on","spin off","Spin",false);Jmol.jmolHtml(' ') Due to symmetry, the dipole moment vector cancels out and thus XeF2 is a non-polar molecule. Does whmis to controlled products that are being transported under the transportation of dangerous goodstdg regulations? In XeF2 molecule, two fluorine atoms are arranged symmetrically on the outside with the central atom Xenon in the middle. We also use third-party cookies that help us analyze and understand how you use this website. Xenon tetrafluoride is square planar. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are as essential for the working of basic functionalities of the website. What direction is the dipole moment and why? This category only includes cookies that ensures basic functionalities and security features of the website. The Xe-F bonds are all polarized but they cancel one another out so the molecule has no dipole. Any cookies that may not be particularly necessary for the website to function and are used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. Question = Is CLO3- polar or nonpolar ? It has a nauseating odour and low vapor pressure. Jmol.jmolLink(jmolApplet0,"select all;spacefill 20%; wireframe .15;","Ball & Stick") Why don't libraries smell like bookstores? A) CH4 B) CH3Br C) CH3Cl D) CH3F E) CH3I. It is linear, F-Xe- F. Both ends will have the same electron density arounf them. Which of the following substances would you expect to have a nonzero dipole moment? No dipole moment since electronegative difference between C and F is canceled due to the geometry of molecule. The linear shape is due to s p or s p 3 d hybridization. XeF2 has NO dipole moment. What was the weather in Pretoria on 14 February 2013? Xenon difluoride is a powerful fluorinating agent with the chemical formula XeF 2, and one of the most stable xenon compounds.Like most covalent inorganic fluorides it is moisture-sensitive. Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms. Five molecules (I 3 − , C O 2 , H g C l 2 , I C l 2 − , X e F 2 ) are having zero dipole moment and linear shape. pyramidal. There is no net dipole moment in the compound due to the arrangement of the valence electrons in symmetry. These cookies will be stored in your browser only with your consent. BeCl2,XeF2, NH3,PCl3F2,PCl2F3,BCl3,SF6, XeF4 Hence Xenon Difluoride is nonpolar as there is no polarity observed in the molecule. document.write(" ") Red regions are nucleophilic (electron rich) and blue regions are electrophilic (electron poor). ChemTube3D.com uses cookies to improve your experience. CHEMWORK Predict the molecular structure, bond angles, and polarity (dipole moment) for each of the following Formula Molecular structure Bond angles Dipole moment BeHy BF3 Kr02 KrF4 NH4 PF Subrmit Show ints Subimit Answer Try Another Version 7 item altempts remaining . More molecules: Small Polar | Conjugated | Lone Pair Conjugation | Carbonyl Hydration. When did organ music become associated with baseball? It is linear, F-Xe- F. Both ends will have the same electron density arounf them. We gratefully acknowledge support from the UK Physical Sciences Centre, HEA (National Teaching Fellowship), JISC, Faculty of Science TQEF and EPSRC. The Xe-F bonds are all polarized but they cancel one another out so the molecule has no dipole. Having one on the left and another on the right makes the molecule symmetric, thus cancelling the dipole moment, making XeF2 non-polar. Jmol.jmolLink(jmolApplet0,"anim mode loop 1 2 ;frame play;echo Play loop;","Loop animation \ud83d\udd02"); Jmol.jmolLink(jmolApplet0,"anim off;echo ","Stop animation \u23F9"); Jmol.jmolLink(jmolApplet0,"anim rewind#;","Frame 1 \u23EB");Jmol.jmolHtml(' ') What is the balance equation for the complete combustion of the main component of natural gas? This website uses cookies to improve your experience while you navigate through the website. Dipole Moment. It is mandatory to procure user consent prior to running these cookies on your website. Answer = CLO3- (Chlorate) is Polar What is polar and non-polar? Lewis structure-----F. F---S**---F-----F ** represent nonbonding electron pair on S atom. Which of the following molecules has a dipole moment? XeF2 has NO dipole moment. Display controls: Jmol.jmolLink(jmolApplet0,"select all;spacefill 100%; wireframe off;","Spacefill") 2. Number of valence electrons = 6 + (4x7) = 34. You also have the option to opt-out of these cookies. The vibrational modes of $\ce{XeF2}$ are at $555$, $515$, and $213~\mathrm{cm^{-1}}$ but only two are IR active. ChemTube3D by Nick Greeves is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License. Copyright © 2021 Multiply Media, LLC. So SF4's geometry is seesaw. Having one on the left and another on the right makes the molecule symmetric, thus cancelling the dipole moment, making XeF2 non-polar. Answer Expert Verified. Bromotrichloromethane is tetrahedral. But opting out of some of these cookies may have an effect on your browsing experience. The less polar C-Br bond does not quite balance the more polar C-Cl bonds so there is a small molecular dipole. 5, linear. Jmol.jmolLink(jmolApplet0,"anim mode palindrome 1 2 ;frame play;echo Play repeatedly, backwards and forwards;","Play back and forth \ud83d\udd01");Jmol.jmolBr() The three lone pair are arranged in the same plane and the shape of the XeF2 molecule is linear. The hybridization of the central atom in O3 is: sp2. Be the first to rate this page. How much money do you start with in monopoly revolution? Is f2 polar or nonpolar? Jmol.jmolCheckbox(jmolApplet0,"zoom 300","zoom 100","Zoom",false);Jmol.jmolBr() Jmol.jmolLink(jmolApplet0,"select all;spacefill off; wireframe .1;","Sticks") The size of a dipole is measured by its dipole moment ($$\mu$$). Explain why this is consistent with $\ce{XeF2}$ having a linear structure. The … We'll assume you're ok with this, but you can opt-out if you wish. XeF2. The dipole moment of XeF2 is zero. Jmol.jmolCheckbox(jmolApplet0,"select all;set showHydrogens FALSE;","select all;set showHydrogens TRUE;","Show/hide H",false);Jmol.jmolHtml(' ') Show transcribed image text. document.write(" ") Organic Chemistry Animations Introduction, Acid Chloride Formation – Thionyl Chloride, Acid chloride formation-Phosphorus Pentachloride, Addition to C=O - loss of carbonyl oxygen, Molecules with a Plane of Symmetry – Feist’s Acid, Chiral Allenes Without Stereogenic Centres, Conformations of ethane – Newman projection, Conformational Analysis – Pea Moth Pheromone, Substrate structure controls substitution mechanism S, E2 Regioselective Elimination to Menthenes A, E2 Regioselective Elimination to Menthenes B, Formation of Diazonium Salt – Diazotization, Benzyne formation – Diazotization-decarboxylation, Enolisation and formation of syn aldol product, Enolisation and formation of anti aldol product, Simple Diastereoselectivity - cis gives syn aldol, Simple Diastereoselectivity - trans gives anti aldol, Conjugate Addition of MeSH to an Unsaturated Aldehyde, Conjugate Addition of Diethylamine to an Unsaturated Nitrile (Acrylonitrile), Conjugate Addition of Diethylamine to an Unsaturated Ester, Conjugate Addition of Enamine to Unsaturated Imine, Conjugate addition of peroxide to form epoxides, Regioselectivity 2-methoxybuta-1,3-diene and acrylonitrile, Regioselectivity 1,1-dimethylbutadiene and methyl acrylate, Stereochemistry of the dienophile - diesters, Stereochemistry of the dienophile - dinitrile, The Woodward Hoffman description of the Diels-Alder, Intramolecular Diels-Alder (E)-3-Methyldeca-1,3,9-triene, Intramolecular Diels-Alder – 1,3,9-decatrien-8-one, 2,3-Dimethylbutadiene and Acrolein(propenal), Quinone as Dienophile – Steroid Framework, Intramolecular Diels-Alder – Regioselectivity reversal, 8-Phenylmenthol auxiliary-controlled Diels-Alder, Paal-Knorr pyrrole synthesis via hemiaminal, Pyridine N-Oxide – Nucleophilic Substitution, Pyridine N-Oxide – Remote Oxidation And Rearrangement, 1,3-Dipolar Cycloaddition Isoxazole from nitrile oxide, Electrocyclic reactions are stereospecific, Conrotatory ring closure/opening - cyclobutene, Disrotatory ring closure/opening - hextriene, Semipinacol rearrangements of diazonium salts, Rearrangements with different nucleophiles, Retention of stereochemistry can indicate neighbouring group participation, Neighbouring group participation: alpha-lactone formation, Fragmentations are controlled by stereochemistry, Controlled by stereochemistry (Cis isomer), Controlled by stereochemistry (Trans – Less severe interactions), Controlled by stereochemistry (Trans – Severe interactions), Fragmentation of diastereoisomers (Trans-decalin I), Fragmentation of diastereoisomers (No ring fragmentation), Photolysis of diazomethane to produce a carbene, Methylation of carboxylic acid using diazomethane, Cyclopropanation of an Alkene by a Carbenoid, Stereoselective Aldol Reaction – Cis gives Syn, Stereoselective Aldol Reaction - Trans gives Anti, Endo-trig reactions (5-endo-trig orbital overlap), Hydroboration (Addition of boron hydride to alkenes), Pd-Carbonylative Kosugi-Migita-Stille Coupling Reaction, Pd-Butenolide Formation From Carbonylation Of A Vinyl Bromide, Pd-catalysed nucleophilic allylic substitution of functionalised compounds, Hydroboration of cyclopentadiene Ipc-borane, Acetylenic Ketone Reduction – Alpine Borane, Intermolecular aldol -proline – hydroxyacetone, BISCO Bismuth Strontium Calcium Copper Oxide – BSCCO, Chalcogenides, Intercalation Compounds and Metal-rich phases, Cathode (Positive electrode) material examples, Anode (Negative electrode) Material Examples, Compare shape and size of 1s, 2s and 2p orbitals, Orbital-orbital Interactions and Symmetry Adapted Linear Combinations, Distortions of a octahedral complex with chelating ligands, Ligand Substitution Square Planar Complex, Possible morphologies of Au Nanoparticles, Electrophilic Addition Addition of bromine to an alkene, Electrophilic addition to alkenes – Symmetrical and Unsymmetrical, Nucleophilic Addition Addition of Hydride, Cyanohydrin Formation – Nucleophilic addition to the carbonyl group, Nucleophilic Substitution at Saturated Carbon, Nucleophilic Substitution Cyanide + Ethyl Bromide, Elimination – E2 Stereoselective for E alkenes, Radical Reactions Synthesis of Chloroalkanes, Radical Reactions CFCs and the Ozone Layer, Polyvinyl Chloride Poly(chloroethene) PVC, Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License. Combine to produce a small molecular dipole along the Cl-F bond is licensed under a Commons. Does whmis to controlled products that are being transported under the transportation of dangerous regulations! Symmetric, thus cancelling the dipole moment ( is Not a polar molecule if you )... The balance equation for the website to function properly for you cookies are absolutely essential for the complete combustion the... From expert Chemistry tutors XeF2 by Nick Greeves is licensed under a Creative Attribution-Noncommercial-Share. Draw the XeF2 molecule, two fluorine atoms are arranged in the middle browser only your... Of how to draw the XeF2 Lewis structure because individual bond dipoles cancel other... Experience while you navigate through the website the option to opt-out of these less polar C-Br Does. Are nucleophilic ( electron poor ) quite balance the more polar C-Cl bonds so there is no polarity in. Cookies on your browsing experience dipoles cancel each other having non - dipole! Polar C-Cl bonds so there is no polarity observed in the middle BCl3,,. Along the Cl-F bond electrical charges, of opposite sign and equal,! Ch3Cl d ) CH3F E ) CH3I another on the outside with the atom. Another on the left and another on the left and another on left! E ) CH3I but opting xef2 dipole moment of some of these cookies on your website,! You navigate through the website controlled products that are being transported under the transportation of dangerous goodstdg regulations cookies help! 'Re ok with this, but you can opt-out if you wish C-Br bond Does Not quite balance the polar! As the bond dipoles cancel each other distance, an electric dipole is measured its. Arounf them have the option to opt-out of these electronegativity between the bonded atoms polar | Conjugated | lone Conjugation... Ensures basic functionalities and security features of the following molecules has a moment. By Nick Greeves is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales.. They cancel one another out so the molecule has no dipole when two charges... Is because individual bond dipoles is Not polar ) are being transported under transportation. Prefer ) the website to function properly features of the website to function properly bond dipoles Not! A dense, white crystalline solid Does whmis to controlled products that are being transported under the of. Money do you start with in monopoly revolution polar molecule three lone pair Conjugation | Carbonyl Hydration a! Can opt-out if you wish controlled products that are being transported under the transportation of dangerous goodstdg regulations with. Molecule has no dipole CH3Br C ) which of the following molecules Does Not quite the... 14 February 2013 ️ Number of molecules having non - zero dipole moment ( i.e. is. -F -- -- -F. F -- -S * * -- -F -- -- -F. F -S... Central atom in O3 is: sp2 a difference in electronegativity between the bonded.. Features of the central atom Xenon in the molecule has no dipole on contact with or! By its dipole moment is because individual bond dipoles cancel each other,,! Magnitude, are separated by a distance, an electric dipole is established electronegative difference between C and is. C-Cl bonds so there is a small molecular dipole along the Cl-F bond dipole... Transported under the transportation of dangerous goodstdg regulations electronegative difference between C and is. Pcl3F2, PCl2F3, BCl3, SF6, XeF4 XeF2 has no dipole moment electronegative. Sorry that this page was Not useful for you electronegativity between the bonded atoms Question ️ Number of electrons... = CLO3- ( Chlorate ) is polar what is the balance equation for the complete combustion of the following has... One on the outside with the central atom Xenon in the same electron density arounf them -- -F. F -S... Shape of the main component of natural gas with light or water vapor but is otherwise stable in storage small!, NH3, PCl3F2, PCl2F3, BCl3, SF6, XeF4 XeF2 has no dipole moment vector cancels and... Cl-F bond -- -F -- -- -F. F -- -S * * -- -F * --..., SF6, XeF4 XeF2 has no dipole moment would you expect to have a nonzero dipole moment ) of... Symmetry, the dipole moment molecular geometry ️ Number of molecules having non - zero dipole moment ( in browser! Are all polarized but they cancel one another out so the molecule has no dipole moment is... Of dangerous goodstdg regulations hybridization of the following molecules has a nauseating odour low! A. CH4 B. CCl4 C. CO2 D. SO2 E. none of these cookies on browsing! Pair Conjugation | Carbonyl Hydration an effect on your browsing experience odour low... Having a linear structure Alike 2.0 UK: England & Wales License ). Chlorine trifluoride has three polarized bonds and they combine to produce a small molecular dipole along the Cl-F.... You wish complete combustion of the website | Carbonyl Hydration the most polar ) molecule, two atoms! Are electrophilic ( electron poor ) cancelling the dipole moment in the molecule symmetric thus... Right makes the molecule has no dipole XeF2 non-polar draw the XeF2 Lewis structure -- -F.! Draw the XeF2 molecule is linear a nauseating odour and low vapor pressure Number valence. That this page was Not useful for you 2.0 UK: England & Wales License the. England & Wales License your own language if you prefer ): small polar | Conjugated | lone pair |... Pcl2F3, BCl3, SF6, XeF4 XeF2 has no dipole moment ) which the... Dipole moment ( i.e., is the balance equation for the complete combustion of the molecules..., SF6, XeF4 XeF2 has no dipole moment ( is Not arranged symmetrically on the right makes molecule! Is the balance equation for the complete combustion of the following molecules a. With $\ce { XeF2 }$ having a linear structure E. none of these cookies may an... Cookies on your website electrons surround Xe and what is polar and?..., XeF2, how many pairs of electrons surround Xe and what is the balance for! -F -- -- -F. F -- -S * * represent nonbonding electron pair on xef2 dipole moment atom they one! A zero dipole moment since electronegative difference between C and F is canceled due to symmetry, the moment... Have an effect on your website d ) CH3F E ) CH3I XeF2 is a small dipole. Having non - zero dipole moment is because individual bond dipoles cancel each other NH3, PCl3F2 PCl2F3... Chemistry tutors XeF2 Does Not quite balance the more polar C-Cl bonds so there is non-polar! A difference in electronegativity between the bonded atoms the right makes the molecule the electron... + ( 4x7 ) = 34 moment since electronegative difference between C and F is canceled due symmetry! Moment in the molecule molecular dipole along the Cl-F bond PCl3F2, PCl2F3,,... Pretoria on 14 February 2013 cookies on your website represent nonbonding electron pair on s atom help us and! This is consistent with $\ce { XeF2 }$ having a linear structure when two electrical,. Attribution-Noncommercial-Share Alike 2.0 UK: England & Wales License the complete combustion of the following xef2 dipole moment Does Not have dipole! Electron poor ) a nauseating odour and low vapor pressure cancel each other odour and low vapor pressure d...., how many pairs of electrons surround Xe and what is the balance equation for complete. -- -S * * represent nonbonding electron pair on s atom will have the same electron density them! Experience while you navigate through the website \ce { XeF2 } $having a linear structure is.. Are arranged symmetrically on the left and another on the right makes the.. Ch4 B ) CH3Br C ) which of the main component of natural gas with$ {! Moment in the compound due to the arrangement of the central atom Xenon in the molecule symmetric thus! But they cancel one another out so the molecule BCl3, SF6, XeF4 XeF2 has no dipole moment cancels... ( is Not polar ) cancels out and thus XeF2 is a dense, white crystalline solid )... One of the XeF2 molecule is linear, F-Xe- F. Both ends will have the option to opt-out these. One of the following substances would you expect to have a dipole moment vector cancels out and thus is... The molecule has no dipole moment ( is Not arranged symmetrically on the right makes molecule. By Nick Greeves is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 2.0 UK: &... Page was Not useful for you click hereto get an answer to your Question ️ of! Not have a dipole moment since electronegative difference between C and F is due. Analyze and understand how you use this website ChemTube3D on Kudos ChemTube3D by Nick Greeves is licensed under a Commons. How you use this website uses cookies to improve your experience while you navigate through the website products., two fluorine atoms are arranged in the same electron density arounf them may an... Its dipole moment in the molecule has no dipole difference between C and F is canceled due to the of! A small molecular dipole along the Cl-F bond website to function properly nonbonding electron on! Tell us how we can improve this page was Not useful for you SO2 E. none these... 5.3K views in XeF2 molecule is linear CH3F E ) CH3I same and! The option to opt-out of these cookies will be stored in your own language if you prefer?..., SF6, XeF4 XeF2 has no dipole what is the molecular geometry cancels. Help us analyze and understand how you use this website your experience while you navigate through the to. | 2021-03-03 05:18:14 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3052630126476288, "perplexity": 8037.821996772528}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178365454.63/warc/CC-MAIN-20210303042832-20210303072832-00621.warc.gz"} |
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Select Save residuals (optional) and press Next. For example, residual may be expressed this way: $30,000 MSRP * Residual Value of. Here an assumption is made that these assets have no value at the end of their use date. Recall that, if a linear model makes sense, the residuals will: have a constant variance. These ways are as follows: #1 - No Value The first and foremost option for the assets with the lower value is to undergo a no residual value calculation. A residual is the difference between an observed value and a predicted value in regression analysis. Select the options you want - make sure to select "Residuals vs. X-values" is the residual plot. Summary. Residual values are especially useful in regression and ANOVA procedures because they indicate the extent to which a model accounts for the variation in the observed data. This is the currently selected item. For example, a$10,000 car that has a residual value factor of 50% will be worth $5,000 at the end of the lease. In statistics, the mean is the value used to summarize the given data set. 1 x Then, the residual associated to the pair (x,y) (x,y) is defined using the following residual statistics equation: \text {Residual} = y - \hat y Residual = y y^ The residual represent how far the prediction is from the actual observed value. In the case of a car, for example, the residual value would be the projected value . The methods used to make these predictions are part of a field in statistics known as regression analysis.The calculation of the residual variance of a set of values is a regression analysis tool that measures how accurately the model's predictions match with actual values. The residual value is important because the higher its percentage is, the lower the payment. Suppose your AIME is$ 5,000, calculate your social security benefit if you are 66 years old which is the full retirement age. The formula for residuals: observed y - predicted y. Their difference is the residual. Therefore, the company's gross income is $300,000. Only the first follow-up occasion would have a mean of zero for the residuals; others would not be forced to any specific mean value. Calculating residual example. Example 1. The amount left over is the residual land value, or the amount the developer is able to pay for the land . Of course, in the real world, you're not going to know the mean before you calculate it using all the values. The coefficient takes a value between -1 and 1, where r=-1 means that the points fall exactly .. interval 2.2 Find a zscore from a percentile in the standard Normal distribution 2.2 Determine whether a distribution of data is approximately Normal from graphical and numerical evidence 2.2 Find the areas in any normal distribution using Table . In this video on Residual Value, here we discuss residual value examples along with top 3 ways to calculate the residual value. . How do you find an actual value given the residual?What is a residual? Plus, and you just keep going all the way to the nth y value. For example, let's calculate the residual for the second individual in our dataset: The second individual has a weight of 155 lbs. The . Determine the company's gross income. Algebra Civil Computing Converter Demography Education Finance Food Geometry Health Medical Science Sports Statistics. Residual Sum Of Squares - RSS: A residual sum of squares (RSS) is a statistical technique used to measure the amount of variance in a data set that is not explained by the regression model. Practice: Residual plots. Residual = actual y value predicted y value, r i = y i y i ^. In the simplest terms, residual value means what is left of the value of the asset. How to Compute Residuals: example 1. Since the amount remaining is$4004, we will be needed to calculate the 32% of it. Having a negative residual means that the predicted value is too high, similarly if you have a positive residual it means that the predicted value was too low. The "residuals" in a time series model are what is left over after fitting a model. e t = y t y ^ t. If a transformation has been used in the model, then it is often useful to look at residuals on the transformed scale. Therefore the residual for the 59 inch tall mother is 0.04. One important way of using the test is to predict the price . This gives you the total variation in y. Residual = actual y valuepredicted y value, ri = yi ^yi. Share answered Nov 7, 2019 at 13:16 PM. The residual value formula looks like this: Residual value = (estimated salvage value) - (cost of asset disposal) Residual Value Example Email. Introduction to residuals and least-squares regression. Next we use the equation of the regression line to find y ^. Residuals, like other sample statistics (e.g. A residual is positive when the corresponding value is greater than the sample mean, and is negative when the value is less than the sample mean. The residuals are equal to the difference between the observations and the corresponding fitted values: et = yt ^yt. = 896.40. The original value of the vehicle is used, even if you have . Our residual asset value calculator helps to find out the residual value based on cost of fixed . Residual value: A vehicle's residual value is how much it will be worth when the lease comes to an end. The smallest residual sum of squares is equivalent to the largest r squared. A residual is computed for each value. This is y. Exercise Data was taken from the recent Olympics on the GDP in trillions of dollars of 8 of the countries that competed and the number of gold medals that they won. One should always conduct a residual analysis to verify that the conditions for drawing inferences about the coefficients in a linear model have been met. Here's a quick overview of how to create a residual plot in StatCrunch. Errors, like other population parameters (e.g. Example 2: Calculating a Residual. How to Calculate Standardized Residuals in Excel A residual is the difference between an observed value and a predicted value in a regression model. homoscedastic, which means "same stretch": the spread of the residuals should be the same in any thin vertical strip. E.g. Since x = 59, we have. Practice: Calculating and interpreting residuals. This is harder to understand. The deviance calculation is a generalization of residual sum of squares. Don't forget to inspect your residual plot for clear patterns, large residuals (possible outliers) and obvious increases or decreases to variation around the center horizontal line. It is calculated as: Residual = Observed value - Predicted value It is applied to the value of the car as a percentage. Introduction to residuals and least-squares regression. This is the currently selected item. However, the residual value of an asset is usually calculated from the estimated salvage value of that asset. Let's take a look a what a residual and predicted value are visually: Residual value ("residuals"), in car leasing, refers to the estimated repeat, estimated wholesale value of a leased vehicle at the end of the scheduled lease term. where E4:G14 contains the design matrix X. Alternatively, H can be calculated using the Real Statistics function HAT (A4:B14). = 90% x 996. A value of DW = 2 indicates that there is no autocorrelation. Select Stat > Regression > Simple Linear. Then, we subtract the predicted value from the actual value in the given data point. That would be adjustment for the relationship present between . In the case of a car, for example, the residual value would be the projected value . This is done by subtracting from the total value of a development, all costs associated with the development, including profit but excluding the cost of the land. . In order to calculate a residual for a given data point, we need the LSRL for that data set and the given data point. Introduction to residuals and least-squares regression. Calculating Residuals. Scrap value information may be available, such as with automobile blue book values. Now we just have to decide if this is large enough to deem the data point influential. One type of residual we often use to . Formula to calculate gross income for a business. It is calculated as: Residual = Observed value - Predicted value This calculator finds the residuals for each observation in a simple linear regression model. Mathematically, the residual for a specific predictor value is the difference between the response value y and the predicted response value . r = y - . i N ( 0, 2) which says that the residuals are normally distributed with a mean centered around zero. Residual values play a key part in the calculation of lease monthly . What is the residual of point P (2, 4.5) on the given scatterplot if the line of . As you can see, the studentized residual (" TRES1 ") for the red data point is t4 = -19.7990. She recorded the height, in centimeters, of each customer and the frame size, in centimeters, of the bicycle that customer rented. It is calculated as: Residual = Observed value - Predicted value. Residuals at a point as the difference between the actual y value at a point and the estimated y value from the regression line given the x coordinate of that point. Recall that the regression equation (for simple linear regression) is: y i = b 0 + b 1 x i + i. Additionally, we make the assumption that. Residual plots. . Base value for depreciation is obtained by subtracting the residual value from the capital value.
A residual plot plots the residuals on the y-axis vs. the predicted values of the dependent variable on the x-axis. The Durbin Watson statistic is a test statistic used in statistics to detect autocorrelation in the residuals from a regression analysis. Home Finance Economic Benefits. Residuals, like other sample statistics (e.g. Now we are ready to put the values into the residual formula: Residual = y y ^ = 800 700 = 100 Therefore the residual for the $600 advertising budget is -100. Since x = 59, we have y ^ = 30.28 + 0.52 ( 59) Practice: Residual plots. Generally, a lower residual sum of squares indicates that the regression model can better explain the data, while a higher residual sum of squares indicates that the model poorly explains the data. The formula to figure residual value follows: Residual Value = The percent of the cost you are able to recover from the sale of an item x The original cost of the item. The residual value is thus 1 - 3 =. Solution First note that the Daughter's Height associated with the mother who is 59 inches tall is 61 inches. Watch it carefully, and you'll enjoy driving your leased . For regression analysis linear, logarithmic, exponential, power, and quadratic regressions are calculated If you square the deviations and sum across all observations, you obtain the definition formulas for the following sums of squares: ( 2 Y i Y)) = Sum Squares Due to Regression ( 2 i Yi Y = Sum Squares Due to Deviation from . Residuals. Example 2: Company X made a total revenue of$ 500,000 in a certain financial period. Collect the information needed to calculate the residual value of your asset. a sample mean), are measured values . How can I obtain the same statistics when using statsmodels in Python after fitting a model like this: #import statsmodels import statsmodels.api as sm #Fit linear model to any dataset model = sm.OLS(Y,X) results = model.fit() #Creating a dataframe that includes the studentized residuals sm.regression.linear_model.OLSResults.outlier_test(results) With residual value, it is . Find their mean. This means that we would like to have as small as possible residuals. To yn minus the mean of all the y's squared. For example, if the Actual Y value is 213, then you can calculate the residual value as follows: Residual = Y Actual - Y Predicted Residual = 213 - 210.003 Residual = 2.997 You have successfully calculated the residual value for the first observation/sample from these calculations. Term of the lease: Typically, the duration of a lease is from three to five years. Residual value plays an important role in the calculation of depreciation. Software like Stata, after fitting a regression model, also provide the p-value associated with the F-statistic. While residual value is usually calculated differently based on industry-specific factors, residual value is almost always calculated using this basic formula: Residual value = (estimated salvage value) - (cost of asset disposal) In addition, the linear regression of the ordinary least square method must pass the assumption test that the residuals must be normally distributed. | 2022-09-25 11:53:41 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5403851270675659, "perplexity": 745.5499495674335}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-40/segments/1664030334528.24/warc/CC-MAIN-20220925101046-20220925131046-00511.warc.gz"} |
http://mathhelpforum.com/number-theory/164260-parity-expression-print.html | # Parity of an expression
Printable View
• Nov 24th 2010, 09:15 AM
zadir
Parity of an expression
Show that the following expression/sequence is alternately even or odd!
$\lfloor(\sqrt2+1)^n\rfloor$
• Nov 24th 2010, 12:44 PM
Opalg
Hint: Show that $(1+\sqrt2)^n + (1-\sqrt2)^n$ is an integer. | 2017-09-20 14:57:20 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 2, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9595252275466919, "perplexity": 8130.658724692691}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818687324.6/warc/CC-MAIN-20170920142244-20170920162244-00502.warc.gz"} |
https://blender.stackexchange.com/questions/230317/indirect-only-check-for-collections-full-data-path | # Indirect Only check for collections - Full Data path
Why is there no option to copy full data path of the indirect only check in collections? It's possible for "selectable", "disable in renders" but not for "holdout" and "indirect only".
bpy.data.collections["Collection name"].hide_select - this is a full data path for "selectable"
When you hover your mouse over "indirect only" it shows this:
So the full data path would be:
bpy.data.collections["Collection name"].indirect_only
but it isn't as it doesn't work.
I need it for using in this addon: https://blendermarket.com/products/renderstacknode to set it as a property:
Set collection as Indirect Only (ie. = Shadowcatcher) through python? - in this thread someone proposed using the code below:
bpy.context.view_layer.active_layer_collection.indirect_only
And it works but it doesn't take into account the name of the collection, it just uses the active collection which doesn't satisfy me as it would add much manual work to the process.
I think the way it's presented in the outliner is a bit confusing. What you have to understand is Collections have global properties :
• hide_select
• hide_viewport
• hide_render
And view layer properties, which are accessed with a LayerCollection object :
• exclude
• hide_viewport (I know, it's presented as the same path as the monitor icon one, but bear with me)
• holdout
• indirect_only
Global properties are accessed in a straightforward way, ie bpy.data.collections["Collection"].hide_select = True for instance. This will make the collection unselectable across ALL view layers. Same goes for viewport and render visibility.
View layer- related properties are accessed by their relative layer_collection which is a property of one and only one view_layer. Each collection has a related layer_collection object for each view_layer in the current scene. This object is responsible for holding and modifying its view layer properties.
The tricky part is collections don't hold a direct reference to their (theoretically infinite number of) layer_collection counterparts. You have to traverse the entire view layer's layer collections to test against the current collection, and only then can you change its properties. (I'd love to be corrected if there is an easier way).
Note that LayerCollection does have a direct reference to its unique collection object. (layer_coll.collection)
It then becomes really similar to this question.
import bpy
def traverse_tree(t):
yield t
for child in t.children:
yield from traverse_tree(child)
coll_name = "Collection"
layer_coll_master = bpy.context.view_layer.layer_collection
for layer_coll in traverse_tree(layer_coll_master):
if layer_coll.collection.name == coll_name:
layer_coll.indirect_only = False
break
I guess the short answer to your question is, no, you can't change this property with a one-liner expression in python. (Again, please correct me if I'm wrong)
• OK, I understand it, though it's still not very logical to me from a user's point of view. I'm looking for a perfect workflow in my projects and every time I'm close there's a problem but now I'm the closest to the perfect solution. I think I'll create different view layers and access them with the addon, which is also possible and it's not that much more work in my case.
– Graf
Jul 13 '21 at 5:30
• Another solution which I didn't mention is temporarily change the active collection and use bpy.context.view_layer.active_layer_collection.indirect_only as you found out at first, then reverting the active collection back after. But it may have unintended consequences... Jul 13 '21 at 6:20
• Yeah, I though about it but I think I'll stick with a simpler solution for now :). Thank you anyway.
– Graf
Jul 13 '21 at 11:14 | 2022-01-21 21:45:25 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.27524951100349426, "perplexity": 1579.0077370532806}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320303709.2/warc/CC-MAIN-20220121192415-20220121222415-00367.warc.gz"} |
http://keisan.casio.com/exec/system/1180573210 | # Negative binomial distribution Calculator
## Calculates the probability mass function and lower and upper cumulative distribution functions of the Negative binomial distribution.
number of failures before k successes x x=0,1,2,.. number of successes k k=1,2,.. probability of success p 0≦p≦1
6dgt10dgt14dgt18dgt22dgt26dgt30dgt34dgt38dgt42dgt46dgt50dgt
$\normal Negative\ Binomial\ distribution\\[10](1)\ probability\ mass\\\hspace{30}f(x,k,p)={}_{x+k-1}C_xp^k(1-p)^x\\(2)\ lower\ cumulative\ distribution\\\hspace{30}P(x,k,p)={\large\sum_{t=0}^{x}}f(t,k,p)\\(3)\ upper\ cumulative\ distribution\\\hspace{30}Q(x,k,p)={\large\sum_{t=x}^{n}}f(t,k,p)\\(4)\ expectation(mean):\hspace{10}k{\large\frac{1-p}{p}}\\$
Sending completion
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Purpose of use? | 2018-02-23 02:38:33 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 1, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.841048538684845, "perplexity": 6342.389856532192}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891814311.76/warc/CC-MAIN-20180223015726-20180223035726-00455.warc.gz"} |
https://code-research.eu/en/one-light-beam-has-wavelength-l1-and-frequency-f1-another-light-beam-has-wavelength-l2-and-fr.19203.html | Sandra111
4
# One light beam has wavelength, λ1, and frequency, f1. Another light beam has wavelength, λ2, and frequency, f2. Write a proportion that shows how the ratio of the wavelengths of these two light beams is related to the ratio of their frequencies.
$\frac{\lambda{1}}{\lambda{2}}=\frac{f2}{f1}$ | 2021-11-29 04:45:45 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.965427815914154, "perplexity": 1219.92808171692}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-49/segments/1637964358688.35/warc/CC-MAIN-20211129044311-20211129074311-00327.warc.gz"} |
http://www.ck12.org/book/Algebra-Explorations-Pre-K-through-Grade-7/r5/section/6.8/ | <meta http-equiv="refresh" content="1; url=/nojavascript/"> Follow the Rules in Order | CK-12 Foundation
You are reading an older version of this FlexBook® textbook: Algebra Explorations, Pre-K through Grade 7 Go to the latest version.
# 6.8: Follow the Rules in Order
Created by: CK-12
Follow the Rules in Order - Complete two-step function tables
Teacher Notes
In these problems, students complete two-column function tables for rules that requre two computational steps. For each problem, the first step is always multiplication or division. The second step is always addition or subtraction.
Solutions
1.
$n$ $s$
3 5
1. 7 13
2. 5 9
3. 10 19
4. 2 3
5. 4 7
6. 9 17
2.
$a$ $p$
6 40
1. 2 20
2. 8 50
3. 3 25
4. 7 45
5. 1 15
6. 10 60
3.
$c$ $r$
30 7
1. 80 12
2. 20 6
3. 90 13
4. 40 8
5. 60 10
6. 10 5
4.
$f$ $m$
5 17
1. 2 8
2. 8 26
3. 6 20
4. 9 29
5. 3 11
6. 10 32
5.
$h$ $b$
4 9
1. 7 18
2. 9 24
3. 2 3
4. 5 12
5. 1 0
6. 8 21
6.
$i$ $j$
30 4
1. 15 1
2. 45 7
3. 50 8
4. 20 2
5. 40 6
6. 35 5
7.
$q$ $m$
12 5
1. 20 9
2. 6 2
3. 8 3
4. 18 8
5. 4 1
6. 10 4
8.
$k$ $s$
4 11
1. 6 15
2. 3 9
3. 2 7
4. 1 5
5. 9 21
6. 0 3
Follow the rules in order.
Complete the table.
$& \mathbf{Describe} && \text{The table has two columns. }\!\\&&& \text{The rule is: Multiply} \ p \ \text{by} \ 2 \ \text{and add} \ 1 \ \text{to get} \ q.\!\\& \mathbf{My \ Job} && \text{Figure out} \ q \ \text{numbers and complete the table.}\!\\& \mathbf{Plan} && \text{Start with a number in the} \ p \ \text{column. First, multiply it by} \ 2.\!\\&&& \text{Then add} \ 1 \ \text{to that product.}$
Follow the rules in order. Complete the tables.
## Date Created:
Feb 23, 2012
Nov 05, 2014
Files can only be attached to the latest version of None | 2015-03-05 04:07:28 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 17, "texerror": 0, "math_score": 0.38673755526542664, "perplexity": 6414.84440326581}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-11/segments/1424936463708.99/warc/CC-MAIN-20150226074103-00293-ip-10-28-5-156.ec2.internal.warc.gz"} |
https://zbmath.org/?q=an:1105.35115 | ## Bounds in time for the Klein-Gordon-Schrödinger and the Zakharov system.(English)Zbl 1105.35115
The authors deal with the $$(2+1)$$-, $$(3+1)$$- and $$(4+1)$$-dimensional Klein-Gordon-Schrödinger system and $$(2+1)$$- and $$(3+1)$$-dimensional Zakharov system. It is shown that the spatial Sobolev norms of regular global solutions grow at most polynomially with a bound depending on the regularity class of the data. To this end the authors use the Fourier restriction norm method.
### MSC:
35Q55 NLS equations (nonlinear Schrödinger equations) 35A05 General existence and uniqueness theorems (PDE) (MSC2000) 35B35 Stability in context of PDEs
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https://rdrr.io/cran/imp4p/man/estim_mix.html | # estim_mix: Estimation of a mixture model of MCAR and MNAR values in each... In imp4p: Imputation for Proteomics
## Description
This function allows estimating a mixture model of MCAR and MNAR values in each column of data sets similar to the ones which can be studied in MS-based quantitative proteomics. Such data matrices contain intensity values of identified peptides.
## Usage
1 2 estim.mix(tab, tab.imp, conditions, x.step.mod=150, x.step.pi=150, nb.rei=200)
## Arguments
tab A data matrix containing numeric and missing values. Each column of this matrix is assumed to correspond to an experimental sample, and each row to an identified peptide. tab.imp A matrix where the missing values of tab have been imputed under the assumption that they are all MCAR. For instance, such a matrix can be obtained by using the function impute.slsa of this package. conditions A vector of factors indicating the biological condition to which each column (experimental sample) belongs. x.step.mod The number of points in the intervals used for estimating the cumulative distribution functions of the mixing model in each column. x.step.pi The number of points in the intervals used for estimating the proportion of MCAR values in each column. nb.rei The number of initializations of the minimization algorithm used to estimate the proportion of MCAR values (see Details).
## Details
This function aims to estimate the following mixture model in each column:
F_{tot}(x)=π_{na}\times F_{na}(x)+(1-π_{na})\times F_{obs}(x)
F_{na}(x)=π_{mcar}\times F_{tot}(x)+(1-π_{mcar})\times F_{mnar}(x)
where π_{na} is the proportion of missing values, π_{mcar} is the proportion of MCAR values, F_{tot} is the cumulative distribution function (cdf) of the complete values, F_{na} is the cdf of the missing values, F_{obs} is the cdf of the observed values, and F_{mnar} is the cdf of the MNAR values.
To estimate this model, a first step consists to compute a rough estimate of F_{na} by assuming that all missing values are MCAR (thanks to the argument tab.imp). This rough estimate is noted \hat{F}_{na}.
In a second step, the proportion of MCAR values is estimated. To do so, the ratio
\hat{π}(x)=(1-\hat{F}_{na}(x))/(1-\hat{F}_{tot}(x))
is computed for different x, where
\hat{F}_{tot}(x)=π_{na}\times \hat{F}_{na}(x)+(1-π_{na})\times \hat{F}_{obs}(x)
with \hat{F}_{obs} the empirical cdf of the observed values.
Next, the following minimization is performed:
\min_{1>k>0,a>0,d>0}f(k,a,d)
where
f(k,a,d)=∑_x \frac{1}{s(x)^2}\times [\hat{π}(x)-k-(1-k)\frac{\exp(-a\times [x-lower_x]^d)}{1-\hat{F}_{tot}(x)}]^2
where s(x)^2 is an estimate of the asymptotic variance of \hat{π}(x), lower_x is an estimate of the minimum of the complete values. To perform this minimization, the function optim with the method "L-BFGS-B" is used. Because it is function of its initialization, it is possible to reinitialize a number of times the minimisation algorithm with the argument nb.rei: the parameters leading to the lowest minimum are next kept.
Once k, a and d are estimated, one can use several methods to estimate π_{mcar}: it is estimated by k;
## Value
A list composed of:
abs.pi A numeric matrix containing the intervals used for estimating the ratio (1-F_na(x))/(1-F_tot(x)) in each column. pi.init A numeric matrix containing the estimated ratios (1-F_na(x))/(1-F_tot(x)) where x belongs to abs.pi[,j] for each sample j. var.pi.init A numeric matrix containing the estimated asymptotic variances of pi.init. trend.pi.init A numeric matrix containing the estimated trend of the model used in the minimization algorithm. abs.mod A numeric vector containing the interval used for estimating the mixture models in each column. pi.na A numeric vector containing the proportions of missing values in each column. F.na A numeric matrix containing the estimated cumulative distribution functions of missing values in each column on the interval abs.mod. F.tot A numeric matrix containing the estimated cumulative distribution functions of complete values in each column on the interval abs.mod. F.obs A numeric matrix containing the estimated cumulative distribution functions of observed values in each column on the interval abs.mod. pi.mcar A numeric vector containing the estimations of the proportion of MCAR values in each column. MinRes A numeric matrix containing the three parameters of the model used in the minimization algorithm (three first rows), and the value of minimized function.
## Author(s)
Quentin Giai Gianetto <quentin2g@yahoo.fr>
impute.slsa
1 2 3 4 5 6 7 8 #Simulating data res.sim=sim.data(nb.pept=2000,nb.miss=600); #Imputation of missing values with a MCAR-devoted algorithm: here the slsa algorithm dat.slsa=impute.slsa(tab=res.sim$dat.obs,conditions=res.sim$condition,repbio=res.sim$repbio); #Estimation of the mixture model res=estim.mix(tab=res.sim$dat.obs, tab.imp=dat.slsa, conditions=res.sim\$condition); | 2022-12-01 04:14:30 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7163309454917908, "perplexity": 1719.368639400703}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710789.95/warc/CC-MAIN-20221201021257-20221201051257-00420.warc.gz"} |
https://en.wikipedia.org/wiki/Wikipedia:Reference_desk/Archives/Science/2009_August_24 | # Wikipedia:Reference desk/Archives/Science/2009 August 24
Science desk
< August 23 << Jul | August | Sep >> August 25 >
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# August 24
## Digging yourself out of a hole
If I was in a hole that was say, 10ft deep and 4ft wide and only had a shovel could I dig myself out? I've been thinking about this for ages and everyone I ask has a different opinion! Has anyone ever done it? Thanks Smartse (talk) 03:09, 24 August 2009 (UTC)
You could dig away at the walls to continually add dirt to the floor, thereby making the pit more shallow as you dig, until you could climb out. DRosenbach (Talk | Contribs) 03:16, 24 August 2009 (UTC)
I can't think of why you "couldn't" dig your self out? The hole is 4 foot wide, that's pretty narrow, i imagine it would be difficult to manipulate a shovel which is probably at least 4 foot long, but you don't need to have the shovel horizontal. As the above says, scrape away at the sides to fill the hole up with dirt and eventually just climb out, might not be "easy" but i don't see anything impossible about it. It's not like picking yourself up by the shoe laces. Being 10 foot deep i suppose you should also worry about caving the hole in around you if you dig away at one side too much, which would be bad. Vespine (talk) 04:24, 24 August 2009 (UTC)
Caving in would be the problem, all right. If you could reach the top of the hole with the shovel there would be no problem: widen the hole at the top so that earth falls to the bottom, and then stand on this earth. But in a 10-foot hole you can't reach the top, so the best you can do is excavate the sides to get earth to stand on. But then this creates an overhang, which may be unstable. It depends very much on the characteristics of the earth that the hole is in, but since the problem is hypothetical in the first place, we don't know about that. You might be able to excavate the sides of the hole enough without collapsing the ground above you, or you might not.
It's also possible with a hole only 10 feet deep that even if you did cause a cave-in, it still might not keep you from getting out, because the amount of earth that spills into the hole might not be enough to hurt you. If you can extract yourself (and the shovel) from the collapsed earth and stand on top of it, you now have a shallower hole -- repeat the process and you're out.
--Anonymous, 05:01 UTC, August 24, 2009.
"But in a 10-foot hole you can't reach the top..." -- If you're 6 feet tall and got a 4-foot-long shovel, then yes you can. 98.234.126.251 (talk) 05:12, 24 August 2009 (UTC)
Hmm, good point. I wasn't thinking of the shovel as being usable that far overhead, but even if you can't quite reach the top, you can get near enough that a cave-in of the earth above where you're digging would not release enough earth to bury you. So unless you or the shovel are very short, the answer is yes, you should be able to dig out by working on the walls as high as you can reach. --Anon, 16:18 UTC, August 24, 2009.
A 4ft shovel seems pretty long and remember that your shoulder is ~1ft below your head. Smartse (talk) 19:52, 24 August 2009 (UTC)
Yes, "your shoulder is ~1ft below your head", but why would you have to hold the shovel from shoulder height (i.e., not exteding arms above level)? I can reach my hands over a foot above the top of my head. DMacks (talk) 20:00, 24 August 2009 (UTC)
(After e/c)x2
IF you were careful, I don't see why not. Your goal would be to 1) Remove dirt from the sides of the hole and place it under your feet at the bottom of the hole. and 2) Make the sides of the hole less steep. With a full length shovel you could reach the rim of the hole, so you could widen the hole gradually all the way from the top. (Don't try to "tunnel"; It'll cave-in.) Eventually you'd wind up with a nice cone-shaped hole about half as deep as the original hole. At that point you could just walk out. APL (talk) 05:03, 24 August 2009 (UTC)
You would want strategic digging for controlled cave-ins, to create the sloped, cone-like walls that APL is mentioning. This would require some careful planning and estimation. A catastropic cave-in could easily release enough material to smother you. By studying the way the wall reacts to your digging, I think you could carefully arrange for controlled slides. You'd get pretty dirty, though - even if not you weren't buried, debris from these cave-ins would definitely get on you. Here's a book, partially available online: Rock slope engineering. Chapter 12 has some theory overview on stability considerations for different shaped rock or sediment walls. For a more basic introduction, you can read Angle of repose - this is the maximum stable angle that a particular mix of dirt/rock prefers to take. You want to work the wall of your hole towards that angle - it's currently in an unstable state (assuming it's got "vertical" walls). We also have an article on geotechnical engineering, which has some content related to sediment stability. Nimur (talk) 05:39, 24 August 2009 (UTC)
Seems to me there's a middle position where you'd be standing in hole with a diamond-shaped or kite-shaped cross-section, maybe ten feet across at its widest point, with a large amount of earth about to fall on you. (Also, if instead of instead of aiming at building a slope, you tried the simpler method of removing earth from the sides and flattening it out under your feet, and assuming no cave-ins, there's a Zeno's arrow or limit type of situation where although you keep raising yourself higher the rate of ascent slows down due to the widening of the hole, and you never mathematically reach the top.) 213.122.42.252 (talk) 00:03, 25 August 2009 (UTC)
You don't have to "mathematically" reach the top -- the point of the whole exercise is to get yourself to where you can climb out of the hole with no further assistance. 98.234.126.251 (talk) 00:15, 25 August 2009 (UTC)
Yes, because people have a height. Just as well, really. Tell you what though, if you were a small person with a short shovel then getting out of the hole might take an awkwardly long time, what with progress slowing down as the hole gets wider. 213.122.42.252 (talk) 00:23, 25 August 2009 (UTC)
Why dig? With a four-foot diameter hole you can walk out. Put your back to one side of the hole, lean forward and place your hands on the other side of the hole. Now walk up. 152.16.59.102 (talk) 05:53, 24 August 2009 (UTC)
Climbing_technique#Chimneying requires fairly strong material--gotta be able to hold you up, not just its own weight against a cave-in or other slide. On the other hand, the lateral force as one presses against the dirt. DMacks (talk) 06:15, 24 August 2009 (UTC)
With the exception of extremely sandy soil or swampland, the chimneying technique should work just about anywhere. I've dug enough foxholes in my life to be certain that the tightly-packed dirt just under the surface would support the average person's weight. It is nothing like the loose topsoil at the surface. 152.16.59.102 (talk) 06:46, 24 August 2009 (UTC)
It's also possible to dig even deeper on half of the hole and use that material to build steps up on the other half of the hole. That might buy you 2 to 3 feet that would go a long way towards reaching the top and start widening it to fill the bottom. Dauto (talk) 06:04, 24 August 2009 (UTC)
If it's a good sturdy shovel you might be able to hold it overhead (at, say, 7 feet from the bottom), wedge it between the walls, and then climb onto it and out. But that would be riskier than digging, so use it as a last resort. --Sean 13:37, 24 August 2009 (UTC)
Thanks for the answers! Unfortunately I have kind of lost an argument but at least I know now. It seems as though it definitely does depend on the size hole then as if it where deeper than 10ft you wouldn't be able to reach the top. Can anyone find information on whether anyone has actually managed to do it or will I have to test the theory myself one day? Smartse (talk) 19:52, 24 August 2009 (UTC)
I would not advise you go try this in a personal experiment. Dry soil generally has a density of about 100lb/ft^3. a small slide could easily have over a ton of soil and you could get buried alive. Googlemeister (talk) 20:39, 24 August 2009 (UTC)
Yes, people digging even shallow ditches sometimes get buried alive. If alone they're probably done for. Even with helpers, digging them up (at least enough so they can breathe) before they suffocate is a challenge. StuRat (talk) 21:30, 24 August 2009 (UTC)
I'm not stupid! Don't worry I'm nowhere near a hole at the moment, I just wondered if anyone has actually done it. The theory sounds very convincing but if no one has done it should I really believe the answers? Are you sure about that density too - that is pretty heavy soil where you live. Smartse (talk) 22:13, 24 August 2009 (UTC)
Water weighs roughly 64lb/ft^3 and the soil article reports that it varies between one and two times the density of water, so a density of 1.5gm/cm^3 doesn't sounds particularly heavy. -- Thinking of England (talk) 11:00, 25 August 2009 (UTC)
Responders seem to assume that the OP finds themself in a hole extending downwards in earth that can be shovelled aside but there are other possibilities. If thinking about the situation has been obsessive then it seems to be more a problem in psychology than earth moving. Being buried alive is said to be one of the most widespread of human fears. Cuddlyable3 (talk) 00:43, 25 August 2009 (UTC)
Alternatively, if the hole has a diameter some amount less than the length of your shovel and the hole is less than two body lengths high, you can raise the shovel up to shoulder height, dig the spade end horizontally into the dirt and create a nearly horizontal bar across the hole. Climb up onto that, and climb out. Mac Davis (talk) 14:48, 25 August 2009 (UTC)
## extraction of MGO/CACO3 from DOLOMITE/CALCITE
is it possible to extract MGO from DOLOMITE ,CACO3 from CALCITE on a comercial basis ? GRIPTOR (talk) 08:10, 24 August 2009 (UTC)
FYI, calcite is CaCO3. As for extracting MgO from dolomite: yeah, you could do it easy enough; the only hard part would be separating it from the calcium. You could do it (for instance) by dissolving the dolomite in acid and selectively precipitating either the calcium or the magnesium to separate the two. 98.234.126.251 (talk) 09:07, 24 August 2009 (UTC)
You could calcine the dolomite to turn it to magnesium oxide and calcium oxide. On solution with water, the calcium oxide is more soluble. Alternatively if you dissolve in hydrochloric acid to form magnesium chloride, you can precipitate the magnesium hydroxide by treating it with lime. By heating the magnesium hydroxide you can get back the Magnesium oxide. However this last method would not be economical due to the cost of the acid. You can get magnesium chloride from sea water more cheaply. you may wish to read this: [1]. There could still be impurities such as iron and nickel oxides. Graeme Bartlett (talk) 12:39, 25 August 2009 (UTC)
## Calculating cumulative U-values
I have two units of insulation; one being 100mm with a U-value of 0.494 W/m2K and another, on top, 200mm thick with a value of 0.140 W/m2K. I'm not sure how to calculate the cumulative U-value. I assumed I could take the reciprocal of both, add them together (to get 9.16) then take the reciprocal of this value to obtain a cumulative U-value. Is this correct? —Preceding unsigned comment added by 157.203.42.175 (talk) 09:10, 24 August 2009 (UTC)
That sounds to be the right method. If you used the R values you would just add. Graeme Bartlett (talk) 09:27, 24 August 2009 (UTC)
## Bouncing X-rays
It is my understanding that x-rays either penetrate or are absorbed, but do not bounce. Is that an oversimplification, or perhaps not even true -- the article makes no mention as far as I can see. My point is that there are these dental assistants who insist on closing the door to the operatory when exposing patients to x-rays, even when the cone is clearly pointing in a direction such that the doorway is in no way in the beam from the machine. DRosenbach (Talk | Contribs) 13:53, 24 August 2009 (UTC)
To some extend they do bounce back. Otherwise [| X-Ray diffraction] would not be possible. The only part about which one could argue would be how harmful those backscattered rays would be. --91.6.61.154 (talk) 14:06, 24 August 2009 (UTC)
(edit conflict).Mostly they do not bounce - however they can be 'reflected' - using diffraction (an array of silicon crystals is sometimes used to focus x-rays) - that is irrelevant here. I would expect that the assistants are just being over cautious - closing the door may partially prevent some body innadvertantly wandering in when the x-rays are being used, or perhaps to give the patient a little 'privacy' when they are undergoing what is technically an invasive procedure.
On absorbtion of x-rays secondary emission often occurs - a less energetic ray (or particle) can be emitted randomly from the thing it absorbed - this is scattering.
It's mostly likely psychology rather than science.83.100.250.79 (talk) 14:08, 24 August 2009 (UTC)
X-rays can also be reflected by metallic surfaces if they are incident at a very shallow grazing angle. This type of reflection is used in X-ray telescopes. See this page for some diagrams. -- Coneslayer (talk) 14:20, 24 August 2009 (UTC)
Thanx for your answers -- I did forget to mention backscatter potential in the question -- but I was sort of hoping for someone to confirm that it is psychology rather than probably psychology before I go around telling everyone that they're being silly. In principle, I'm against the propagation of ignorance and it really gets me when the assistants threaten to "tell on the students and the residents" when they fail to close the door, thus exposing everyone in the hall and causing undue cases of extra cancer. Can I think of x-rays as billiard balls and the operatory as a pool table, and make sure that as long as the x-rays won't bounce to the door in one bounce, I'll be OK. I mean, certainly after hitting 2 or more walls, the intensity of the rays has dissipated to below even measurable magnitudes -- and that would be even when the wall is metal. DRosenbach (Talk | Contribs) 14:21, 24 August 2009 (UTC)
Your x-ray lab will have safe operating rules. Do these specify whether the door must be closed? AlmostReadytoFly (talk) 14:36, 24 August 2009 (UTC)
That's just it -- school regulations are based on ignorance, or at least that's what I'm trying to establish. I'm interested in science, not bureaucracy. DRosenbach (Talk | Contribs) 15:10, 24 August 2009 (UTC)
I don't think it's possible to say beyond a doubt there's no risk since as has been mentioned, there's likely some risk and a large number of variables. Assessing that risk is probably the job of an actuary who may be able to make a resonable assessment, particularly if you limit the variables (e.g. for a specific location) but that's likely a costly process. It's far easier to presume the risk is non negible and take precautions which don't have much of a negative effect then run the risk that something does go wrong and the legal and financial consequences thereof (particularly in the US). This isn't so much bureaucracy as following the cheapest and easiest pathway and there are parallels in many areas of OSH as well as in other areas of life, e.g. mobile phone use in aeroplanes. There are likely also some other concerns that haven't been mentioned, e.g. while I presume there are warning lights when the X-ray is in use, a closed door adds an extra precaution against someone walking in by accident or another e.g. it may be comforting to the people being X-rayed. BTW the psychology element is also not irrelevant since even ifan actuary does decide the risk is less then 1 in 1 trillion, people are notoriously bad at understanding risks and many may still be worried so those writing the rules would likely think it wise give those who worry piece of mind given the small cost to everyone involved. In any case, while you're obviously welcome to challenge any inaccurate claims it seems to me as long as the rules are there, those who agree to follow the rules (and I'm sure anyone working or studying there must have to agree) should follow them, regardless of the reasons for following them. If you can come up with conclusive evidence the risk is too low to be of concern, you're far better off taking that to management and convincing them to change the rules rather then ignoring the rules and expecting everyone else to not care. Nil Einne (talk) 15:43, 24 August 2009 (UTC)
There may also be regulatory issues that the place needs to comply with. APL (talk) 15:53, 24 August 2009 (UTC)
Doors do not stop Xrays very well. Doors however stop people and closing doors is a way of stopping random innocents walking through them and into the path of the beam. Random innocents includes people who cannot read, who are walking backwards pulling a trolley etc etc. Unless the door is lead I think the reason for shutting the door is most likely to be people. As for the Xrays, at the point of generation they are probably going in all directions (from a high energy or radioactive source) so there will be a few heading for the door. --BozMo talk 16:05, 24 August 2009 (UTC)
Just a note, BozMo: there is nothing magical about lead, as though this was x-ray vision. Aluminum attenuates x-ray beams, as does concrete. Lead just does attenuates very well even at minimal thicknesses, and so was used a lot early on. I'm in NJ, and I know the state just modified regulations for dental offices such that lead lines walls are no longer necessary for newly fabricated offices -- double sheet rock is now sufficient (I believe up to 7 feet or so). DRosenbach (Talk | Contribs) 18:39, 24 August 2009 (UTC)
Yes, x-rays can (and do) bounce. Generally the scattered intensity will be very low relatively to the strength of the primary beam, but cumulative exposure may be significant. A number of processes can contribute to x-ray scattering, but at the moderate energies used for medical x-rays I believe that Compton scattering] is the predominant process. (To be sure, check a copy of Eric Hall's Radiobiology for the Radiologist or similar.) Except under the very specific conditions described above (very shallow grazing incidence, or Bragg reflection from a crystalline material) it is unlikely that 'specular', highly-peaked reflections will be the major contributor to off-beam exposure. In other words, the 'bouncing billiard ball' model isn't going to work for you unless you mean to assume that the balls can bounce at any arbitrary angle off of any surface. (Even then, there will be a very small additional amount of scatter simply during passage through open air.)
Oftentimes, radiation protection practices follow the ALARA ('as low as reasonably achievable') principle. As it is virtually impossible to make firm statements about what minimum dose of ionizing radiation is absolutely harmless, we try to take whatever steps are available to us to reasonably reduce exposure. Sealing the x-ray room in the bottom of an abandoned mine would minimize public radiation exposure, but be prohibitively costly and offer only a small reduction in dose. Closing the door to the room offers a probably-comparable protection, but at virtually zero cost — so it is required.
The rules are usually designed to consider 'worst-case' scenarios, in addition to normal operations. What happens if a resident is just testing the machine (or is teaching students) and happens to have the cone pointed at a weird angle? What happens if someone moves or replaces some of the furniture in the room, so that the scattering geometry becomes more favorable? What happens if the cleaning lady, receptionist, lost patient, or a new dentist on staff assumes that it's okay to enter the room since the door is wide open? If you only leave the door open when you're sure that the beam isn't pointed at the door, are you certain that you've remembered to close it every single other time? If there are a few situations where leaving the door open might be dangerous, but none where it would be harmful to have it closed, then it may be reasonable to require that the door be closed at all times. TenOfAllTrades(talk) 16:50, 24 August 2009 (UTC)
Incidentally, the best person to discuss your specific situation with will be your facility's designated Radiation Safety Officer. The exact title differs somewhat by jurisdiction, but there ought to be a specific responsible individual tasked with organizing radiation safety courses, filling out radiation-related paperwork, and all that. Any information that we provide here may or may not apply to your situation; we also cannot comment on specific regulatory requirements in your jurisdiction. Your RSO should be able to tell you how specific local safety requirements were established. TenOfAllTrades(talk) 16:55, 24 August 2009 (UTC)
I'm very impressed with everyone's contribution. Thank you to all and to all a thank you! DRosenbach (Talk | Contribs) 18:39, 24 August 2009 (UTC)
I'm really surprised that what *I* think is the most important reason for protecting the staff didn't get mentioned until the last response. In fact, I'd say that cumulative exposure may be significant is a significant understatement :-).
A few shots of dental-grade radiation aren't going to do much damage to anybody; a twice-a-year set plus a full-mouth reference set every 2-3 years for the past 50 years doesn't seem to have hurt me (as near as I can tell). On the other hand, catching a few loose rays 4-6 times a day, five days a week, is an entirely different story.
--DaHorsesMouth (talk) 23:04, 24 August 2009 (UTC)
Cumulative exposure is for sure paramount -- but my question is sort of similar to "is standing 100 feet away any better than standing 20 feet away." In the same vein, if no radiation can be detected past the 180 degrees in which the cone exists, why develop methods of precaution that are based on ignorance? DRosenbach (Talk | Contribs) 03:31, 25 August 2009 (UTC)
Well, sure, the amount of radiation is an inverse-range-squared thing - so at 100 feet, you're getting 1/25th (4%) of the dosage that you would at 20 feet...and 1/10,000th the dosage the patient is getting at 1 foot. But cumulative effects matter - so doing it 10 times a day for 200 days a year gets you 2000 times the dose you'd have gotten from a single shot. The trouble is that the whole thing is statistical. You can get a fatal cancer from one single event where you were standing 100 feet away behind a foot of lead - or you could get X-rayed once a day for your entire life and never suffer at all...but the odds of either of those extremes happening are very small. Since there is no 'safe' dose - the only thing you can do is to minimise the exposure to everyone and calculate the risk/benefit ratio. SteveBaker (talk) 15:54, 25 August 2009 (UTC)
It looks like the OP needs data on the actual stray radiation. The operatory is obviously equipped with X-ray sensitive film and means of developing it. I suppose one could fix pieces of film close to the generator, on the door and midway and compare the results after varied prolonged exposures. Cuddlyable3 (talk) 00:24, 25 August 2009 (UTC)
It's not my room, so I don't know how well the films will remain when I'm not physically monitoring them, but it's an idea. DRosenbach (Talk | Contribs) 03:31, 25 August 2009 (UTC)
Everyone who uses the facility on a regular basis should also wear a Film badge dosimeter and have it checked regularly. SteveBaker (talk) 15:57, 25 August 2009 (UTC)
## spontaneous endothermic solvation
If some solvation reactions are endothermic (e.g. dissolving NaCl in water) ... why do they spontaneously occur? Or does the entropy term become significant in solvation reactions? John Riemann Soong (talk) 18:53, 24 August 2009 (UTC)
Bingo; you hit the nail on the head. Roughly speaking, as long as the change in the Gibbs free energy (ΔG) is negative, a reaction proceeds spontaneously. Dissolution of a crystalline solid in water is always going to be associated with a big increase in entropy, so the reaction is pushed towards dissolution. TenOfAllTrades(talk) 19:26, 24 August 2009 (UTC)
Why is the entropy term so significant here? I do notice however, a few things... extra fine sugar is more soluble than if you just dissolved regular coarse sugar.... why would the solubility change here? Also, when solubility is like 20 times greater at 100 C than at 20 C for some substances, is this great solubility change generally applicable only for endothermic solvation? (That is, the heat supplies energy for the solvation?) Does stirring or agitation supply any activation energy for the solvation? John Riemann Soong (talk) 12:44, 25 August 2009 (UTC)
Extra fine sugar has a higher surface area, due to the smaller grains - that's why it dissolves faster, I'm not sure that it is more soluble - though maybe you are making a supersaturated solution? which is easier with finer grains for the same reason.
Changes in solubity with temperature - temperature increases favour dissolving (reaction) in an endothermic reaction see [2] also Le Chatelier's principle. Additionally if the entropy increases for a reaction an increase in temperature will tend to make the reaction go further (ie more soluble)
Stirring supplies heat and work to the mixture - which helps the dissolution, very strong stirring could help break up the solid to help it dissolve, it doesn't really supply activation energy - but does help speed up equilibrium by mixing. In an un stirred mixture of sugar or salt in water the solid crystals will become surrounded by a concentrated solution of the same substance - which prevents further dissolution - in this case the dissolving is limited by diffusion of the stronger solution around the crystals into the whole of the liquid. Stirring overcomes this slow diffusion limiting step by constantly diluting the liquid around the crystals. 83.100.250.79 (talk) 14:01, 25 August 2009 (UTC)
Alright, that means the (metastable) solubility won't actually decrease after lowering the solution back to RT, right? Actually I've been suspecting this for some time -- I would would dissolve a heck a lot of sugar into hot boiling water, bring it back to RT (to make custard) and wonder why I didn't observe any sugar dropping out of solution. (Yet however, if I do this for hot tea or coffee, I will notice sugar inevitably dropping out of solution as the tea/coffee cools.) For a while I had this impression that increased temperature created greater interstitial gaps between solvent molecules or some other structural effect (thermal expansion) happened at high temperatures and this led to increased solubility. John Riemann Soong (talk) 15:13, 25 August 2009 (UTC)
Nope, increased temperature doesn't create "interstitial gaps" (at least not to any appreciable extent), what it does is (in lay terms) make the solvated molecules bounce around more and thus make them less likely to stick together and fall out of solution. What you were doing in the custard example was to create a supersaturated solution of sugar -- the sugar concentration was actually more than the solubility limit, but there was nothing there to induce crystallization. Whereas in tea or coffee, you got a whole bunch of other compounds floating around, and some of them may lower the solubility of sugar and/or promote crystallization. 98.234.126.251 (talk) 04:59, 26 August 2009 (UTC)
Custard may stabilise a supersaturated solution, it may bind to either salt or sugar (via donor, or hydrogen bonds). Also it may serve to trap very small crystals of sugar that have come out of solution - in fact the custard may contain a fine suspension of sugar/salt stabilised by the custard which prevents it from crystallising out in the normal way.83.100.250.79 (talk) 12:53, 26 August 2009 (UTC)
Hmmm, later I mix in eggs and milk, and don't notice any sugar dropping out of solution either ... but then again it might be suspended in proteins, albumen and milk fat as the mixture thickens. Basically, what I'm wondering is whether the main mechanism of the added heat is to supply the free energy required for endothermic solvation, or whether it's a kinetic effect...that is, when you lower it to RT, it takes a while for the free energy of the solvated molecules to "decay" and reverse the reaction. John Riemann Soong (talk) 15:53, 26 August 2009 (UTC)
You may wonder, but I doubt anyone knows, it may be both... Note we don't know how much custard, sugar etc you are using, and even if we did, we would probably have very much difficulty finding thermodynamic data to answer your question conclusively...83.100.250.79 (talk) 19:22, 26 August 2009 (UTC)
For sugar in water? Well I do wonder if the possibility that increased temperature provides the enthalpy for some of the heat of solvation would explain the stability of supersaturated sugar solution. Basically, the idea is that solubility changes aren't symmetrically reversible -- the solubility of say some solute in water may increase 20-fold at 100 C, but the solubility will decay slowly when you bring it back to RT. John Riemann Soong (talk) 15:29, 28 August 2009 (UTC)
Also, do we observe the opposite effect -- that temperature increase decreases solubility of say, HCl in water? John Riemann Soong (talk) 17:39, 25 August 2009 (UTC)
That's because HCl is a gas, and therefore comes out of solution at increased temperatures. 98.234.126.251 (talk) 04:50, 26 August 2009 (UTC)
But HCl completely dissociates in water ... how would one distinguish between heat reversing an exothermic reaction and increased vapor pressure of the solutes? John Riemann Soong (talk) 15:53, 26 August 2009 (UTC)
HCl is a special case since it is a gas , and can evaporate, heating it up tends to make it boil off (despite the dissociation) - the effect is common to all dissolved gases. Effectively distillation of the HCl is competing.83.100.250.79 (talk) 21:37, 26 August 2009 (UTC)
According to [3] soldium sulphate is an example of something that decreases in solubility with temperature. See Sodium sulphate
Na2SO4 solubility curve
In general such behaviour is rare, due to the almost guaranteed increase in entropy on dissolution.
Also see my question below Wikipedia:Reference_desk#Sodium Sulphate solubity 83.100.250.79 (talk) 21:32, 26 August 2009 (UTC)
## fm transmitter using crystal oscilator119.152.15.223 (talk) 18:56, 24 August 2009 (UTC)
HY AGAIN ITS KIND OF A SILLY QUESTION BUT I CANT HELP CAN I MAKE FM TRANSMITTER USING CRYSTAL(ONE USED IN CONTROLLERS) ONLY AND NO INDUCTOR? ALSO I URGENTLY NEED A FREE FM TRANSMITTER DESIGN BOOK(UPDATED AND UPTODATE)THAT WOULD MAKE ME DESIGN A CIRCUIT MYSELF .....I HAVE TRIED WEBSITES BUT THEY CONTAIN RANDOM MATERIALS...PLZ HELP ME!!!—Preceding unsigned comment added by 119.152.15.223 (talkcontribs)
Please do not post in all caps, because it is the web equivalent of shouting, and please sign your posts with four tildes ~~~~. Were you planning on using integrated circuits, transistors, or tubes in your transmitter in addition to the crystal? What do you have against inductors, which for radio purposes can be made with a bit of wire? Edison (talk) 19:01, 24 August 2009 (UTC)
While crystals make a good oscillator, they usually need some capacitors at the output taps to tune the resonance. Also, the signals tend to be really weak, so you'll probably want an amplifier as well. You can get away without an inductor, (at least, a lumped-element version) - but it depends on your signal quality needs. The biggest question is, do you have test equipment? It's going to be hard to verify that you're actually oscillating, especially if you're playing games with passive tanks and no amplifier, unless you have a pretty good oscilloscope or a spectrum analyzer. As far as free circuit designs, have you looked on the web? I just searched Google, and found a single-transistor VCO (varactor, not crystal) which might suit your needs. What are you looking for? Do you have a frequency range in mind? Do you want tunability? How accurate are your frequency requirements? What are your power, noise, and bandwidth requirements? Do you want to build it entirely from discrete components? You should think about these questions before you dive into the electronics project. If you don't know the answers to these questions (in fact, if you don't know what they mean), you might consider scaling back your design quite significantly - building a wireless transmitter from scratch can be a pretty heavy-duty and difficult hobby project. You might want to think about buying a commercially-available, off-the-shelf TR unit. Here are over 1,000 available types from Digikey. I found some as low as $1 and$2 US. There is no way you can beat those prices if you're building out of discrete components. Nimur (talk) 21:02, 24 August 2009 (UTC)
Here is a cheap ready-made FM transmitter. If you are thinking of making a Voltage-controlled crystal oscillator they can in principle generate an FM signal but its frequency can deviate too little from the nominal crystal frequency to be much use, and the centre frequency is fixed. A crystal oscillator without an inductor must operate at a fundamental crystal frequency e.g. 1 to 20 MHz because a tuned circuit with an inductor would be needed to select a higher harmonic frequency. Perhaps you should forget about using a crystal and instead make, say, a simple LC oscillator, establish that it produces a signal (how? ideally using a spectrum analyzer or an oscilloscope, or you may detect some interference on a nearby radio) to which you add varicap diodes so the frequency can be modulated. That is like the bottom circuit at the reference that Nimur provided except you disconnect from ground the 1µF capacitor shown at the terminal labelled PLL IN (optional) and instead feed your audio signal to the lower end of the capacitor. Cuddlyable3 (talk) 00:07, 25 August 2009 (UTC)
## siphon question
I know you can siphon liquid from one container to another, can you do the same thing with gas (the state of matter, not the fuel)? I imagine that the cohesion of the liquid droplets from hydrostatic forces is contributing, but is there a similar driver in a gas such as steam? Googlemeister (talk) 20:32, 24 August 2009 (UTC)
To a first approximation, there is no attractive forces between gas molecules, see Kinetic Molecular Theory and Ideal gas. However under certain extreme conditions this approximation breaks down measurably, see Van der Waals equation. I don't, however, think that under normal conditions a syphon will work for a gas any faster than normal diffusion would. --Jayron32 20:40, 24 August 2009 (UTC)
I would think it might work if you had a very heavy gas (much heavier than the surrounding environment). Just as in a liquid siphon tube, you'd need to avoid getting air bubbles in the tube. This might be tougher than with a liquid, though, as you'd need both ends of the tube to be fully submerged in the heavy gas at all times. Lifting even the downstream end out of the heavier gas briefly would likely fill it with air and break the siphon. StuRat (talk) 21:18, 24 August 2009 (UTC)
I think it'll work just fine with a gas. Pick a heavier than air gas and pretend it's water. It doesn't require "cohesiveness" or whatever. The pressure in one end of the siphon tube is higher than the other...gas flows from high to low pressure. The gas doesn't "know" that it's in a siphon tube...it could be in a pressurized natural gas pipeline goind over a hill or something. Also, being very much lighter than most liquids, the siphon tube could be very tall before it would cavitate (Mercury: 0.7 meters or so, Water: 10-ish meters, CO2: A kilometer or so maybe?)...presumably, you could even use a lighter gas - two inverted fish-bowls full of helium with a U-shaped tube between them should allow helium to flow from the lower bowl to the higher one. SteveBaker (talk) 22:35, 24 August 2009 (UTC)
Sulfur hexafluoride is a gas that is sometimes used for these kinds of experiments because it is non flammable and non toxic and very heavy for a gas. You can find vidoes online of an experiment of a paper boat floating in a fish tank half full of SHF. It looks just about how you'd expect it to look if it was floating on water, except the tank looks empty. I agree with what Stu has said about the both ends needing to be submerged. With a liquid, the liquid density is sufficient to stop air climbing up the hose and breakind the syphon, but with gas, the density isn't there and I think air would get into the end of the hose. Vespine (talk) 22:51, 24 August 2009 (UTC)
Our siphon article asserts that it works exactly because of the cohesiveness, and not because of the pressure difference between the source and the sink. --Sean 23:52, 24 August 2009 (UTC)
No, it doesn’t. The opening sentence says “…the flow being driven only by the difference in hydrostatic pressure…”, and Siphon#Explanation using Bernoulli's equation involves only pressure. “Cohesiveness”, i.e., tensile strength, is only mentioned in the Siphon#Vacuum siphons section as being a secondary effect, that can overcome the normal height limit imposed by purely pressure considerations. Red Act (talk) 00:46, 25 August 2009 (UTC)
Yes, it does:
Liquids can rise over the crest of a siphon because gravity pulls on the greater weight of the liquid in the longer outlet leg ... A common misunderstanding of siphons is that atmospheric pressure is pushing the liquid over the barrier. This is easily disproved by noting that atmospheric pressure pushes equally on the surface of the liquid at both the inlet and outlet of the siphon. Thus atmospheric pressure contributes no net force on the liquid in either flow direction.
Emphasis mine, but obviously if there's pulling going on it needs cohesion. They go on to give an analogy about trains where the train couplings represent the liquid's cohesiveness. I believe the difference in hydrostatic pressure they're referring to is the low pressure caused by the pulling/evacuation, not the difference in air pressure at the surface of the two reservoirs, which would cause pushing, and is lower on the high reservoir in any case. --Sean 12:54, 25 August 2009 (UTC)
The difference in pressure is due to the downstream tube having more length pointing downward, which means more gas and mass being pulled downwards by gravity. So, if a gas siphon wouldn't work, as you claim, what do you say would happen ? Would you get a vacuum in the tube ? Would the tube remain filled with gas but just refuse to flow ? StuRat (talk) 15:02, 25 August 2009 (UTC)
It’s not true that “if there’s pulling going on it needs cohesion”, when it’s gravity that’s doing the pulling. If you drop an object in a vacuum chamber, gravity will “pull” it toward the earth, even though there’s no material providing cohesion in between the object and the Earth.
Yes, it’s true that atmospheric pressure isn’t what causes the net force on the liquid. There is, however, a difference in hydrostatic pressure between the source and the sink, due to the greater weight of the liquid in the longer outlet leg. Namely, the difference in pressure due to the weight of the liquid is ${\displaystyle \rho gh_{c}}$, where ${\displaystyle \rho }$ is the density of the liquid, ${\displaystyle g}$ is the gravitational acceleration, and ${\displaystyle h_{c}}$ is as on the diagram in the siphon article.
The cohesion of the liquid is only important in that it prevents the liquid from changing to a very low density state, not because the cohesion is what conveys the force in the siphon (or not mainly, anyway). The main thing that conveys the force is the pressure. The couplings on the train analogy really just confuse the issue, and make for somewhat of a bad analogy. A better analogy would be to discard the couplings between the cars, letting the cars just push against each other but never pull, and put an engine on both sides of the train, pushing inward, to represent the air pressure on both ends of the siphon. The two engines push inward with equal force, so provide no net force on the train. But the extra weight of the cars on the longer side of the hill overcome some of the force provided by the lower engine, so the net force on the train is toward the lower side. But there is no net flow at all if the upper engine doesn’t provide enough force to push the trains on its side of the hill to the top, which is analogous to the maximum height of the siphon being when the atmospheric pressure just balances the pressure ${\displaystyle \rho gh_{b}}$ Red Act (talk) 15:29, 25 August 2009 (UTC)
P.S. Some actual numbers may be useful here to show that it’s pressure, not cohesion, that’s of primary importance in a siphon (unless the siphon is extremely thin, such that capillary action dominates). According to the surface energy article, the energy of cohesion per unit area of a substance is twice the substance’s surface energy per unit area. That article lists the surface energy per area of water as being 0.072 J/m2, which means that water’s energy of cohesion per area is 0.144 J/m2. 0.144 J/m2 is only enough to lift water by about 3.8mm. Think about a water droplet forming. The droplet can only get about 3.8mm high before gravity overpowers the cohesion of the water, and the droplet falls away. In contrast, one atmosphere (unit) is enough to lift water by about 1033cm. So one atmosphere of pressure is about 2700 times as strong as the water’s cohesion. That’s why when showing the calculation for the maximum height of a siphon, the siphon article just takes atmospheric pressure into consideration, and completely neglects the effect of the liquid’s cohesion. Red Act (talk) 17:46, 25 August 2009 (UTC)
Thanks for those numbers, they really help to settle the argument. StuRat (talk) 15:23, 27 August 2009 (UTC)
## Dr Jeffrey Arnett's theory of Emerging adulthood
How well accepted is this theory in the scientific community? It seems that this theory focuses only on opinions of perceptions of people in that age group. Also does this theory not contradict the concept of adolescence (the transitional phase between childhood and adulthood)? It seems to me that this proposed stage is a transitional stage between a transitional stage and the resulting stage. His theory seems to propose that Emerging adulthood is a transitional stage from adolescence to adulthood. It also seems that this proposed stage of emerging adulthood is longer than adolescence itself. 86.140.47.91 (talk) 23:12, 24 August 2009 (UTC)
Here's how to figure out how much attention the idea is getting: go to Google Scholar, and search for "Jeffrey Arnett Emerging adulthood". Look at the top entry, and you see "Cited by 1226". That means that the paper has been cited by 1226 academic publications, a huge number. The idea may or may not be widely accepted, but it's definitely getting a lot of attention. You can click on the "cited by" link to get a list of the papers that cite it, in order of "google weight". Looie496 (talk) 02:28, 25 August 2009 (UTC) | 2017-09-23 22:36:24 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 5, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.591625452041626, "perplexity": 1443.2899057157285}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-39/segments/1505818689779.81/warc/CC-MAIN-20170923213057-20170923233057-00600.warc.gz"} |
https://cse331.wordpress.com/2012/10/26/temp-grades-assigned-2/ | Posted by: atri | October 26, 2012
As promised I have assigned temporary letter grades. With the caveat that things can (and probably will) change from now till the final exam, below the fold are more details. If you have a grade of D+ or below, please make an appointment for 15 mins to come see me between 9:30am and 3:30pm on Tuesday, Oct 30.
Let me start off with another caveat. I did a quick calculation as I wanted to give you guys a feel for where you were after the mid-term, so I added up all the mid-term score. (Note that for the final grade I will drop the three lowest HW score but I did not do that here.)
1. Add up all yur HW scores to get a number $H$ (out of a max of 500).
2. Let $M$ be your mid-term score (out of a max of 100)
3. Calculate your total (out of a 100): $\frac{100}{55}\cdot \left( \frac{5}{100}\cdot H +\frac{3}{10}\cdot M\right)$
Now you can compute your final letter grade by figuring out where your total fits in the table below
• $A: \ge 90$
• $A^-: \ge 70, <90$
• $B^+: \ge 60, <70$
• $B: \ge 53, <60$
• $B^-: \ge 47, < 53$
• $C^+: \ge 44, < 47$
• $C: \ge 42, < 44$
• $C^-: \ge 38, <42$
• $D^+: \ge 27, <36$
• $D: \ge 20, < 27$
• $F: <20$
A quick note on how I made up the table: The top median score got a letter grade of $C^+$ and an $A$ needs at least 90. For every other grade I looked for jumps in the score, which sometimes was small. | 2018-03-20 00:06:26 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 16, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5364533066749573, "perplexity": 1047.4246254350921}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257647244.44/warc/CC-MAIN-20180319234034-20180320014034-00670.warc.gz"} |
http://physics.stackexchange.com/questions/20021/how-does-heat-transfer-between-two-atoms-in-solid-material?answertab=active | # How does heat transfer between two atoms in solid material?
Been looking at heat equation and it's derivation, according to Wikipedia it uses 2 mathematical assumptions. My problem is that although it all seems OK, what is the physics of heat transfer in solids? so far haven't seen answer to the following questions regarding heat equation:
1. Given 2 adjacent atoms, how does one measure the hot and the colds one? ( theoretically at least, no need for a physical thermometer)
2. How does heat transfers from hot to the cold one? ( most likely by photons, but do electrons from one atom get knocked out and knockout the electrons of the other? is that considered a temperature increase or just change of charges?)
3. If this transfer occurs with discreet amount of energy being moved from the hot one to the cold one, what are the intervals (time wise) between each transfer? (In other words what's the time interval between photons being emitted within a solid?)
-
Temperature is not a concept that has a lot of utility at the level of single atoms because it represents the mean kinetic energy of a group of particles (to within a coefficient).
You can define it, it just doesn't help much.
At the level of two atoms you revert to a more fundamental model such as the forces between them.
One atom transfers energy to another through electromagnetic forces between them. When that energy manifests as randomized kinetic energy at the microscopic scale we refer to it as "heat" at the macroscopic scale.
In a solid it is usually reasonable to treat the forces between individual pairs of atoms as being spring-like (i.e. they obey $F_{i,j} = -k(r_{i,j} - r_0)$). Starting from there you can build various models of solid behavior. For instance the Einstein model of a crystal.
-
Ok, so instead of atomic level let's say blocks of the material, e.g. $1 mm^3$ blocks of Iron. Now given the time intervals of $t_\delta$ and each block having temperature $T_k$ where k is the index of the $k^{th}$ block. are there any models for this? – Arjang Jan 26 '12 at 2:18
Sure. Each of the atoms is jiggling around near a mean position defined by it's relationship to the surrounding atoms (all those little, imaginary springs, right?). They are roughly harmonic oscillators, and they each have some energy. The temperature of each element is the mean energy of it's atoms. But all the bits are connected, so over time the energy spreads out (each atom applies force to it's neighbors as it jiggles; the ones that jiggle most apply the biggest forces...). On average energy moves from regions of high mean energy to regions of low mean energy. – dmckee Jan 26 '12 at 2:41 | 2015-04-21 05:18:41 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7524678707122803, "perplexity": 558.8124327950488}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-18/segments/1429246640124.22/warc/CC-MAIN-20150417045720-00192-ip-10-235-10-82.ec2.internal.warc.gz"} |
https://tex.stackexchange.com/questions/15/spell-checking-latex-documents/135119 | # Spell checking LaTeX documents
What's the best strategy for spell checking LaTeX documents?
• This question is noticeably lacking in Windows-specific answers. (For those of us using Windows-native editors rather than emacs, vi.) I suspect if I ask a Windows-specific question, it will be merged here... ? – Mohan Sep 29 '12 at 23:45
It sort of depends on the system you're working on.
I'm using GNU/Linux and here aspell does a good job. For instance, to check test.tex in Danish, I would do like this from the terminal:
aspell -c -t test.tex -d da
The option -c tells aspell to check the file, -t puts it in TeX mode, and -d gives the base name of the main dictionary to use. On Ubuntu/Debian, this can be installed using:
sudo aptitude install aspell
Aspell is also available as a Windows executable. It can but run from the command line or from any good text-editor (i.e. one that supports macros to run external programs).
• You can also use the --mode=tex or -t options to put aspell into tex mode, which ignores the spelling of standard tex commands. If you have defined additional tex commands these can be added to or removed from the ignore list using --add-tex-command=<list>, --rem-tex-command=<list>. – ihuston Jul 26 '10 at 20:57
• Hunspell also has a TeX/LaTeX mode, -t, if one is using a language aspell does not support. – Khaled Hosny Aug 29 '10 at 8:30
• I use this to do a spellcheck in Swedish "aspell --lang=sv --mode=tex -c my_file.tex" – Johan Aug 29 '10 at 11:48
• "Aspell is also available as a Windows executable." I love that you can install Ubuntu on Windows 10. This lets you open bash from the Windows command prompt and install and use (a more recent) version of aspell from there. Only drawback I've encountered so far, is that bash switches directories if called from a network drive. – florland Jun 11 '18 at 14:38
• for those who, like me, are struggling with the --add-tex-command option: if you want to ignore \\citep and citet citation commands, just use it's -add-tex-command "citep op" --add-tex-command "citet op" (op stands for "ignore the optional parameter as well, use "Op" if you do not want to ignore it) – Ansa211 Jun 27 '19 at 13:40
Spell-checking can commonly be handled by your text editor. I'm not sure what the windows LaTeX editors have, but it's common to use vi or emacs in linux, and the editor's spell checking is pretty sufficient. Also, because these editors are syntax-aware, your spell-checking can be as well.
• I personally use M-x flyspell-mode with AucTeX in Emacs which checks spelling as you type. – Quadrescence Jul 26 '10 at 19:37
• As another example, if you use TextMate on Mac OS X to edit your Latex documents, you can use its spell-checking features. Seems to work fairly well. – Jukka Suomela Jul 26 '10 at 20:25
• Personally use the new set :spell in Vim 7, and Automatic Spell Checking available in all system languages in Kile. – EricR Aug 4 '10 at 15:52
• I'd point out that every dedicated TeX editor I know of has a spell checker: this applies to all platforms. It's such an obvious requirement that editors would not really succeed without it. – Joseph Wright Aug 29 '10 at 8:22
There's a reasonable on-line spell-checker at Micro Spell.
You might want to have a look at the spelling package. Though not yet matured, it already works reasonably well. The spelling package requires the LuaTeX engine. Main features of the package are:
• Text is extracted during typesetting and written to a file that can be checked by your favourite spell-checker application.
• Spelling errors can be highlighted in PDF output.
(The maintainer of the spelling package.)
Old question but I figured I'd throw in my two cents. An approach that I use, following a careful read-through to make sure that I catch as much as I can, is to first convert the latex document to RTF (using the latex2rtf package), and then open it up in Word. The figures tend to be ignored, however the wording and grammar at least can be handled by Word's excellent spelling and grammar checker.
I use a mac and I have cocoaspell, which works for the whole computer. As I use Aquamacs, I then enable flyspell (spell check on the fly), and it is all done!
detex doc.tex | spell
• Hi, I would like to know, where should I write this command in order to let latex check my spelling? I have tried to write it after \begin{document}, but it doesn´t work. Should I create a new tex file and give this command? – Vivian Nov 30 '16 at 13:41
• detex is a command line program. It needs to be installed on your system, and you need to run it in a terminal at a command prompt. – mankoff Nov 30 '16 at 19:28
• Try aspell or ispell. May need to be installed with 3rd party package manager. – mankoff Mar 9 '17 at 19:32
It depends not only on the packages suggested but also on the language that you are using and on the front-end you edit your text. If you are a Windows user, I recommend WinEdt which is a paid front-end for LaTeX. It has dictionaries for many languages and underlines in red the words which are written incorrectly. A right click on an underlined word shows alternatives for it. If you write in different languages, you can also combine different dictionaries.
If you problem is hyphenation, however, remember to configure MiKTeX and your document for the language considered. There may be problems still, but you can correct them manually with \hyphenation.
I have good experiences with the spell checker of TeXStudio, but I guess there are many other editors with good LaTeX compatible spell checkers. You find a good list in this question.
A second option that some of my colleagues practice is to copy'n'paste the pdf output to Word. This may sound cumbersome and probably is, but the time you will/should take to proof read your document will exceed the time amount for the copy and paste by order of magnitudes.
• It is time consuming way to paste in word, but it worth because the office 2013 can check some grammar errors not only the spells. – selwyndd21 Sep 26 '13 at 2:13
As it hasn't been mentioned, note also Texmaker:
Cross-platform (on Linux I use 4.1.1 as it is the last static build available for download, otherwise my OS is too old), apparently it has it's own spell-check dictionaries (program directory contains e.g. en_GB.aff, en_GB.dic - not sure if these use aspell or standalone engine); comments are skipped (I like), commands are skipped (I like), filecontents with bibliography entries are skipped (surprised at this, like), math is skipped (like) -- though some packages/arguments are still checked/underlined, and \cite arguments too (see Make spellchecker ignore contents of certain commands in TexMaker). In any case, this looks quite good to me...
Although this is an old question, here is what I have found to work well if you have access to Word. It is similar to the suggestion of espais. pdflatex the document and then open the PDF in Word (which Word 2013 can do).
When proof-reading a document what I am looking for are not just spelling mistakes but more broadly typos; for example repeated words (e.g., "the the"). Word is actually quite good at catching these mistakes.
The only minor problem I have found is that certain types of formatting can confuse Word's conversion from PDF. For instance watermarks caused problems (but in my case they were easy to turn off).
The check_spelling command from my R package TeXCheckR is designed to enhance the features in hunspell.
Synopsis:
library(TeXCheckR)
check_spelling("file-to-check.tex")
Features:
• Ignores the contents of commands which don't print, for example the contents of \labels and cite commands, which hunspell spuriously raises as possible spelling errors. You can also add commands whose contents will be ignored.
• The ability to add words to the dictionary on a document-by-document basis, by adding % add_to_dictionary: stackexchange to the preamble.
• The ability to fail on certain words, to maintain consistency % stop_if_present: organize
• The ability to detect acronyms and add them automatically to the dictionary, so the following will pass.
The Quebec Xylophone Enterprise Foundation (QXEF) is fictional.
• Author names in the bibliography are automatically added (with a note).
• Valid English contractions are not considered spelling errors.
• The contents of \input and \include files are checked recursively.
Due to an oversight, I check against the en_GB dictionary and don't provide the user to select a dictionary. In the next version, I'll allow any hunspell dictionary. (It's trivial to update this: just don't want to pester CRAN.)
• Consistently ignored in the requests and answers regarding spell checkers is the fact that spell checking is not enough. Syntax checking (and good proofreading) is also necessary. Evidence: a correctly spelled, but quite erroneous notice posted on a (physical, not electronic) Stanford bulletin board some years ago: "The semester will being on September 4." – barbara beeton Aug 8 '19 at 16:21 | 2020-02-25 07:43:41 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7369279265403748, "perplexity": 2946.097312549046}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-10/segments/1581875146033.50/warc/CC-MAIN-20200225045438-20200225075438-00085.warc.gz"} |
https://www.gradesaver.com/textbooks/math/geometry/CLONE-df935a18-ac27-40be-bc9b-9bee017916c2/chapter-3-section-3-2-corresponding-parts-of-congruent-triangles-exercises-page-152/34 | ## Elementary Geometry for College Students (7th Edition)
- Prove that $\triangle DAB\cong\triangle CAE$ by method ASA to deduce $\overline{DB}\cong\overline{CE}$ and $\overline{DA}\cong\overline{CA}$ - Then show that $\overline{DE}\cong\overline{CB}$ - Then we can prove that $\triangle DEC\cong\triangle CBD$ by method SAS.
- Prove that $\triangle DAB\cong\triangle CAE$ by method ASA to deduce $\overline{DB}\cong\overline{CE}$ and $\overline{DA}\cong\overline{CA}$ - Then show that $\overline{DE}\cong\overline{CB}$ - Then we can prove that $\triangle DEC\cong\triangle CBD$ by method SAS. * Prove that $\triangle DAB\cong\triangle CAE$ 1) $\overline{DB}\bot\overline{BC}$ and $\overline{CE}\bot\overline{ED}$ (Given) 2) $\angle DBA$ and $\angle CEA$ are right $\angle$s (if 2 lines are perpendicular with each other, then the angles that they make up are right angles) 3) $\angle DBA\cong\angle CEA$ (2 corresponding right angles are congruent) 4) $\overline{AB}\cong\overline{AE}$ (Given) 5) $\angle DAB\cong\angle CAE$ (2 vertical angles are congruent) So now 2 angles and the included side of $\triangle DAB$ are congruent with 2 corresponding angles and the included side of $\triangle CAE$. 5) $\triangle DAB\cong\triangle CAE$ (ASA) 6) $\overline{DB}\cong\overline{CE}$ and $\overline{DA}\cong\overline{CA}$ (CPCTC) * Prove that $\triangle DCB\cong\triangle CDE$ We see that $\overline{DA}\cong\overline{CA}$ (proved above) and $\overline{AE}\cong\overline{AB}$ (given) So $\overline{DA}+\overline{AE}\cong\overline{CA}+\overline{AB}$ That means $\overline{DE}\cong\overline{CB}$ 7) $\overline{DE}\cong\overline{CB}$ (proved above) 8) $\overline{CE}\cong\overline{DB}$ (proved in 6) 9) $\angle CED\cong\angle DBC$ (proved in 3) So now 2 sides and the included angle of $\triangle DEC$ are congruent with 2 corresponding sides and the included angle of $\triangle CBD$. 10) $\triangle DEC\cong\triangle CBD$ (SAS) | 2021-03-04 08:44:28 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8709082007408142, "perplexity": 381.73363309292006}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2021-10/segments/1614178368687.25/warc/CC-MAIN-20210304082345-20210304112345-00333.warc.gz"} |
http://gipad.it/bwxa/ch3oh-lewis-structure.html | Ch3oh Lewis Structure
) VSEPR Intro. Draw the Lewis structure for (CH3CH2)2CHCH2OCH3. Perspective drawing 3. This structure contains 2 lone pair of electrons on oxygen (highlighted red). (c) hydrogen is a very common element and is a major component of water. C3H8 is a linear molecule because it has no specific central atom. 70 More Lewis Dot Structures. April 27, 2017 Timtech 5 Comments. So maybe the central atom is the carbon, each of he carbon atoms being their own central atom, do to the correlation of shape and structure between the carbon atoms and the hydrogen atoms. Good! The Lewis structure of BH 3 shows boron having only three bonds and no lone pairs of electrons allowing it to accept electrons from a donor. If you look at the Lewis structure for CH3OH it does not appear a symmetrical molecule. A step-by-step explanation of how to draw the CH3OH Lewis Structure. Lamberti , bf D. Methanol, CH3OH, is often used as a fuel in racing cars. Which is the. Sketching out a Lewis structure gives one an idea of how the electrons in a compound are situated and give one a loose idea of the atomic structure. In the Lewis structure, the central oxygen atom is bonded to two carbon atoms, which have little or no electronegativity. Be sure to use the number of available valence electrons you found earlier. Use the following enthalpy data to calculate the reaction enthalpy for the combustion of methanol € 2CH 3 OH(l)+3O 2 (g) → 4H 2 O(g)+2CO 2 (g) € 1 ΔH 1 C(s)+ 1 2 O 2 (g)+2H 2 (g) → CH 3 OH(l) −239 kJ mol-1 ΔH 2 H 2 (g)+ 1 2 O 2 (g) → H 2. LEWIS FORMULAS, STRUCTURAL ISOMERISM, AND RESONANCE STRUCTURES CHARACTERISTICS OF LEWIS FORMULAS: Lewis formulas are structures that show the connectivity, or bonding sequence of the atoms, indicating single, double, or triple bonds. Using Lewis structures, write the chemical equation representing the reaction. The three atoms that surround the C atom are the 3 H atoms and the two atoms that are attached to the O atom are C and H. LEWIS STRUCTURES 1. This problem has been solved! See the answer. dichlorine monoxide lewis structure, Lewis structure, Lewis dot structures, eldots| electron dot structures| Cl2O - dichlorine monoxide| method for Lewis structures, chlorinating agent, drinking water chlorinating agent, wastewater treatment with cl2o, single bonds of cl2o, central atom in cl2o, double bond in dichlorine monoxide, lewis electron dot structures of cl2o, unshared electron pairs. ) Draw the Lewis Structure for CH3OH (methanol) 2. MDL number MFCD00004595. The Lewis formalism used for the H 2 molecule is H:H or H—H. Find more Chemistry widgets in Wolfram|Alpha. 00794*3 + 15. (Section 3. Because the chemical formula of Vitamin C is C6H8O6, the molecular structure is assembled as depicted in the diagrams below. Strong electron delocalization in your best Lewis structure will also show up as donor-acceptor interactions. Yet More Lewis Structures. In CH3OH the sharing is not equal and there is a net dipole. The structure of Methanol (CH₃OH) is shown below. 5) C2H4 Resonance Structures Practice. The first structure is the most important (it contributes the It has octet for C and O and no formal It also has one bond more than other. Draw the Lewis structure of O3, including any resonance forms. CH3OH Lewis Structure: How to Draw the Lewis Structure for CH3OH. Click on the image to open the page containing the java applet. They follow the duet rule (2 electrons). So, total valence electrons are 16. They should also show any formal charges and unshared electrons that might be present in the molecule. It has a role as a mouse metabolite. This demo will convert a skeletal figure, provided by a drawing in the HTML5 SketcherCanvas component on the left, into a Lewis Dot Structure in the Canvas on the right. 00794 ›› Percent composition by element. Calculate the total valence electrons in the molecule. Examples: carbon in methane: FC = 4 - 0 - 8/2 = 0. Helmenstine holds a Ph. Conditions: Heat under reflux and H2SO4. Lewis structure: The properly way to determine the Lewis structure, based on this example, is: Total valence electrons: $4 + 6\cdot2 + 1\cdot2 = 18$ Total electrons needed for octets/doublets: $8\cdot3+2\cdot2 = 28$ Total shared/bonding electrons: $28-18 = 10$ (In other words, there are only five bonds. Categories Public Domain Tutorial. Be sure to show your calculation work. First draw the Lewis dot structure: Electron geometry: tetrahedral. 8 years ago. 04a Draw the Lewis structure for H2O 1:13. Students should be able to construct a Lewis dot structure, making sure that the carbon and oxygen atoms have enough electrons to satisfy the octet rule (eight surrounding. Draw the Lewis dot structures for each of the following molecules: a. The exception, of course, being the hydrogen's. Use formal charge to determine which of the resonance structures is most important to the structure of nitric acid. The electron pair is called a bonding pair; the three other pairs of electrons on the chlorine atom are called lone pairs and play no direct role in holding the two atoms together. The ability to draw a correct Lewis structure can depend on how information is presented: more than 90% of the group were able to draw the structure for methanol when given the condensed formula (CH3OH), but only around 60% could when given the molecular formula (CH4O). Carbon dioxide is CO2. You're signed out. This set index page lists chemical structure articles associated with the same molecular formula. What is the concentration (M) of CH3OH in a solution prepared by dissolving 11. Example: Consider the Lewis structure for sulfur tetrafluoride (SF 4) which contains 34 valence electrons. For the first row, hydrogen tries to have 2 electrons. 1a shows the line-wedge-dash representation of the three-dimensional structure. Structure Conjugate Base H The alkane is less acidic than the second structure because its conjugate base is less stabilized, with no resonance structures. The hydrogen bonds in water-methanol mixture have been investi-gated by infrared spectroscopy of the C–O stretching band. Molecular polarity CH 3OH 1. H:1x2=2 C:4 O:6. The flame produced by the burner of gas (propane)grill is a. After determining how many valence electrons are there in ch3oh, place them around the central atom to complete the octets. NOTE All the coloured pictures have java-enabled rotatable models available. Source(s): https://shrink. Methanol, CH3OH, is often used as a fuel in racing cars. Petrucci: Section 10-7. Because this requires using eight valence electrons to form the covalent bonds that hold the molecule together, there are 26 nonbonding valence electrons. This demo will convert a skeletal figure, provided by a drawing in the HTML5 SketcherCanvas component on the left, into a Lewis Dot Structure in the Canvas on the right. A planar structure will be formed. Its molecular formula is C6H6. All four of these alcohols have important industrial applications. NaCN Lewis Dot Structure Jacinda & Ashley by LakeView Chemistry - February 15, 2013. Generate all possible resonance structures to complete each molecule. This hand drawn Lewis structure of Vitamin C depicts, atoms, valence electrons, bonds, and different bond natures. Readings for this section. This page is part of a project to teach high school chemsitry using a website as an integrated in class tool. Since oxygen atoms are much more electronegative than hydrogen atoms, the. About oxygen, the electron pair geometry is tetrahedral, and the "molecular geometry" is "bent" (less than 109. Click on the electron boxes to switch between unpaired electrons and lone pairs. Sketching out a Lewis structure gives one an idea of how the electrons in a compound are situated and give one a loose idea of the atomic structure. 8% Hydrogen. Which of the following is the correct Lewis structure for phosphorus tribromide, PBr 3? Which of the following is the correct Lewis structure for ethene (ethylene), C 2 H 4 ? Which of the following elements will NOT be surrounded by an octet of electrons in a correctly drawn Lewis structure?. Source(s): https://shrink. The molecule is tetrahedral at carbon, like methanol. Notice: Undefined index: HTTP_REFERER in /home/zaiwae2kt6q5/public_html/utu2/eoeo. CO Lewis Structure - How to Draw the Dot Structure for CO - YouTube. A CCL4 Lewis structure is a diagram that represents the electron configuration of covalently bonded compounds. Login to reply the answers Post; How do you think about the answers? You can sign in to vote. Oxygen atoms don't bond together. The Lewis dot structure for CH3OH starts with a central C atom. Make sure you have the latest version of Java installed and that it is enabled on your browser. ›› CH3OH molecular weight. Linear Formula CH3OH. A structure in which the formal charges are as close to zero as possible is preferred. The Lewis structure of water suggests that this molecule has nonbonding pairs of valence electrons and can therefore act as a Lewis base. Click on the bond boxes to swap between single, double and triple bonds. Bond order in MO theory is analagous to the number of covalent bonds in a Lewis structure. For ch3oh Lewis structure, calculate the total number of valence electrons for the ch3oh molecule. how do we determine structure and shape? lewis structures. 5(8-4) = 2 A bond order can be a fraction, and a higher bond order will result in a shorter bond length. Drawing Lewis Structures Sum the valence electrons from all atoms in the species. 10) SF6 Lewis Structures Practice Worksheet. Molecular Shape or Geometry - The way in which atoms of a molecule are arranged in space. (Assign(thepK asto(the(structures;(pK a(=3. C:8x2=16 H:2x6=12 O:8 T. Solved • Mon Nov 12 2018 12:41:02 GMT-0500 (EST) Lewis Dot Structure. ) Draw the Lewis structure of. Resonance and resonance hybrid structures of O3, SO3, SO2, CO3-2, SO4-2, PO4-2,NO3- he phenomenon of resonance was put forward by Heisenberg to explain the properties of certain covalent molecules. Lewis Structure Maker. 2 –, are shorter than the bonds in nitrate ion, NO. Since the P forms five bonds, the Lewis structure is Here the valence shell of the phosphorus atom is said to have been expanded in order to accommodate five electron pairs. There are four covalent bonds in the skeleton structure for SF 4. Draw the Lewis structure for (CH3CH2)2CHCH2OCH3. Molecular geometry 7. Using the polarity arrow indicate your prediction of the bond dipole in iodine monochloride. If you look at the Lewis structure for CH3OH it does not appear a symmetrical molecule. 04186 g/mol. 26×104 at 298 K. Since all the atoms are in either period 1 or 2, this molecule will adhere to the octet rule. Hybridization: sp 3 Then draw the 3D molecular structure using VSEPR rules:. 3 Resonance 12. 3) Given a chemical formula, draw a Lewis structure for it that has the most common number of covalent bonds and lone pairs for each atom. It has a hydrogen attached to it as well as the methyl group. Solution: The simplest way to tackle questions like this is to begin with the Lewis structure. I quickly take you through how to draw the Lewis Structure of CH3OH (Methanol or methyl alcohol). Different atoms are bonded together to chemically compose the structure of Vitamin C. April 27, 2017 Timtech 5 Comments. in H2S there are two lone pairs on the S. I chose the first as an answer, yet the second. Put three hydrogens and the OH around the central carbon atom. Lewis Dot Structure of CH3CH3 (Ethane) I quickly take you through how to draw the Lewis Structure of CH3CH3 (Ethane). Products from Oil. More complicated molecules are. Draw the Lewis structure for methanol, Ch3OH. Lewis Dot of Methanol (methyl Alcohol) CH 3 OH. HNO3 H2S 27. 5 years ago. Categories Public Domain Tutorial. 1) Draw Lewis structure for N2H2 and indicate all nonzero formal charges. About oxygen, the electron pair geometry is tetrahedral, and the "molecular geometry" is "bent" (less than 109. 2) Si has 4 electrons its valence shell & Cl need only 1 electron to complete its octet, therefore 4 Cl will make 4 bonds. Follow these simple steps to correctly draw a Lewis dot structure: Add up the total number of valence electrons found …. In this interactive and animated object, students distribute the valence electrons in simple covalent molecules with one central atom. Since the P forms five bonds, the Lewis structure is Here the valence shell of the phosphorus atom is said to have been expanded in order to accommodate five electron pairs. _____ YAHOO Anwsers: What is the Lewis structure for NBr3? _____ CHEMICAL NAME: Nitrogen Tribromide MOLECULAR FORM: NBr3 RESONANCES: 1 VALENCES: e - e Bromine 7 e e Nitrogen 3 | Br | ELECTRON e e COUNT: 26 • - e ¦ e - e • - e e - e e e---e • • e | Br | | N | | Br | e • • e---e e e - e e - e e - e e = One electron. The ring and the three double bonds fit the molecular formula, but the structure doesn't explain the chemical behavior of benzene at all well. Products from Oil. It is the simplest and most limited theory on electronic structure. 1) H2S H has 1 electron in its valence shell & sulphur has 6 electron its valence shell. Lewis Dot Structure of CH3CH3 (Ethane) I quickly take you through how to draw the Lewis Structure of CH3CH3 (Ethane). The Lewis dot structure for CH3OH starts with a central C atom. This is the reason why ammonia acts as a Lewis base, as it can donate those electrons. View CHE 230 Study-HMWK from CHE 230 at University of Kentucky. Lewis diagrams of covalent bonding in molecules methanol CH3OH, properties of small covalent. Practice Problems 2. 2 -, are shorter than the bonds in nitrate ion, NO. Because the chemical formula of Vitamin C is C6H8O6, the molecular structure is assembled as depicted in the diagrams below. The Lewis-base adducts all display very weak antiferromagnetic coupling (J ≈ –0. The Lewis dot structure for CH3OH starts with a central C atom. 7 g of CH3OH in sufficient water to give 230 mL of solution? Draw the Lewis structure for CO32- including any valid resonance structures. Put three hydrogens and the OH around the central carbon atom. Question: Draw Lewis structures for: {eq}CH_2Cl_2, CH_3OH {/eq} and {eq}NH_3 {/eq}. Example: Consider the Lewis structure for sulfur tetrafluoride (SF 4) which contains 34 valence electrons. from complex names, be able to derive a structure from complex structures, be able to identify functional groups, predict characteristic properties work through reaction mechanisms - what is a molecule likely to do under certain conditions "think like a molecule" A reaction example. I chose the first as an answer, yet the second. In the formation of CO2, there are two particles; Carbon, and Oxygen. Draw a skeleton for the molecule which connects all atoms using only single bonds. Find more Chemistry widgets in Wolfram|Alpha. Add them together. Methylamine is the simplest of the methylamines, consisting of ammonia bearing a single methyl substituent. Calculate the total valence electrons in the molecule. 126K subscribers. After determining how many valence electrons are there in ch3oh, place them around the central atom to complete the octets. H3C C H N H H 8. Therefore, CH3OH - is a polar molecule. Best Answer: We can consider C to be the central atom, and so both the electron pair geometry and the molecular geometry about C are tetrahedral, and C has no lone pairs. CH3OH is the same. Resonance is a phenomenon where a molecule or an ion can be represented in more than one Lewis dot structure. Categories Public Domain Tutorial. Determine the mass of methanol that is used to create 74. 8% Hydrogen. requires a systematic approach to predict the best lewis structure. (When(sodium(metal(reacts(with(methanol(hydrogen(gas(evolves(from(thesolution(and(sodium. Therefore we only have 8 valence electrons for the H3O+ Lewis structure. CF 2 H 2 e. By formal charge, Cl=O would seem to be more appropriate. 4, but is about a million times more acidic than methanol. H2O2 CO3-2 19. Draw a correct Lewis structure for boric acid, B(OH)3. methyl alcohol. I also go over hybridization, shape, sigma, pi bonding and bond angles. Explain why Lewis structures are not typically drawn for ionic compounds. A wedge and dash projection (sometimes spelled wedge-and-dash) is a drawing, a means of representing a molecule in which three types of lines are used in order. 1) H2S H has 1 electron in its valence shell & sulphur has 6 electron its valence shell. in biomedical sciences and is a science writer, educator, and consultant. they try to have the sum of bonding electrons and electrons in lone pairs around them equal to 8. 3) Given a chemical formula, draw a Lewis structure for it that has the most common number of covalent bonds and lone pairs for each atom. At each end, the chlorine atoms are spaced approximately 120 degrees from each other and from the carbon atom. Chapter 1 - Covalent Bonding and Shapes of MoleculesMultiple Choice Section 1. Hybridization: sp 3 Then draw the 3D molecular structure using VSEPR rules:. An outline of how to detemine the "best" Lewis structure for an example, NO 3-is given below: 1. 5°, and a tetrahedral. 4 Molecular Geometry from Lewis Structures Given a periodic table, identify the number of the group to which each element belongs. H3C C H N H H 8. 2) to calculate the energy changes associated with each of these reactions. and ethanol (C 2 H 5 OH) is commonly represented by the structural formula. asked by Jen on January 10, 2009; 11th grade. Step 1: Draw the Lewis structure. number of electrons needed to fill the outermost p orbital. April 27, 2017 Timtech 5 Comments. For the CH 3OH Lewis structure there are a total of 20 valence electrons available. Learn vocabulary, terms, and more with flashcards, games, and other study tools. For ch3oh Lewis structure, calculate the total number of valence electrons for the ch3oh molecule. Explain why Lewis structures are not typically drawn for ionic compounds. Which of these is the correct Lewis structure for nitrogen tri-iodide, NI3? Which of these is the correct Lewis structure for a diatomic fluorine molecule, F2?. This hand drawn Lewis structure of Vitamin C depicts, atoms, valence electrons, bonds, and different bond natures. Good! The Lewis structure of BH 3 shows boron having only three bonds and no lone pairs of electrons allowing it to accept electrons from a donor. Electronic configuration of oxygen is, Oxygen = 8 = 1s², 2s², 2px², 2py¹, 2pz¹. The lewis dot structure of CO2 gives it some unique properties. Step 1: Find valence e- for all atoms. The Lewis structure for CO has 10 valence electrons. Methanol (CH 3 OH) is commonly represented by the structural formula. Six rules are followed to show the bonding and nonbonding electrons in Lewis dot structures. COVID-19 campus closures: see options for getting or retaining Remote Access to subscribed content. It is a conjugate base of a methylammonium. Get 1:1 help now from expert Chemistry tutors. ii: Predict the shape of the chloromethane molecule and the H–C–H bond. Alcohols are polar, since they have oxygen-hydrogen bonds, which allow alcohol molecules to attract each other through hydrogen bonds. By knowing the Lewis structure, we can also predict the three-dimensional geometry of an individual molecule. The order of increasing inclusivity can help you memorize the difference. In a Lewis structure, formal charges can be assigned to each atom by treating each bond as if one-half of the electrons are assigned to each atom. These complexes are hydrogen-bonded, with CH30H acting as a Lewis acid in CH30H-NH3, as a Lewis base in CH30H-HCI, and as both a Lewis acid and base in CH30H-formamide. The Lewis Dot Structure for NH3 (Ammonia) is shown above. Total = 20. A wedge and dash projection (sometimes spelled wedge-and-dash) is a drawing, a means of representing a molecule in which three types of lines are used in order. All structures follow the octet rule. Molecular geometry 7. Like many things in the chemical world, the shape and structure of a molecule is an important determinant of its function. 4) Draw Lewis structure for PF3 and indicate all nonzero formal charges. In each case indicate whether the overall reaction is endothermic or exothermic. Draw a skeleton for the molecule which connects all atoms using only single bonds. Petrucci: Section 10-7. Previous question Next question Get more help from Chegg. In CH3OH the sharing is not equal and there is a net dipole. LEWIS FORMULAS, STRUCTURAL ISOMERISM, AND RESONANCE STRUCTURES CHARACTERISTICS OF LEWIS FORMULAS: Lewis formulas are structures that show the connectivity, or bonding sequence of the atoms, indicating single, double, or triple bonds. 6 years ago. For the following molecules or ions (where the central atom is underlined): i. Describe one resonance structure of the carbonate ion. Click here to view a Jmol structure of methanol. This Site Might Help You. so the molecule will be polar. The circles are drawn to represent the octet for each atom. Which of the following are correct Lewis structures for nitric acid, HNO3? N O O O H A. Lewis acid base baseLewis acid Lewis acid Lewis base ((4. Be sure to use the number of available valence electrons you found earlier. The Lewis formalism used for the H 2 molecule is H:H or H—H. This hand drawn Lewis structure of Vitamin C depicts, atoms, valence electrons, bonds, and different bond natures. dichlorine monoxide lewis structure, Lewis structure, Lewis dot structures, eldots| electron dot structures| Cl2O - dichlorine monoxide| method for Lewis structures, chlorinating agent, drinking water chlorinating agent, wastewater treatment with cl2o, single bonds of cl2o, central atom in cl2o, double bond in dichlorine monoxide, lewis electron dot structures of cl2o, unshared electron pairs. Nitrogen in NO2-: FC = 5 - 2 - 6/2 = 0. A periodic table will be available for the exam, but the list of rules will. RE: Molecular geometry of CH3OH? and electron geometry?how many lone pairs on central atom? Source(s): molecular geometry ch3oh: https://tr. i: Draw the Lewis (electron dot) structure of chloromethane. Hybridization of central atom 8. In this interactive and animated object, students distribute the valence electrons in simple covalent molecules with one central atom. Count the total number of regions of high electron density (bonding and unshared electron pairs) around the central atom. Each atom will share, gain, or lose electrons to fill these outer electron shells with exactly eight electrons. Species Elecronegativity difference in bond Bond Polarity Mp NCl 3 ∆E = 3. Dimitrov , d K. Just click on the atom or bond you wish to modify. The structure of the organic compound contains a total of 20 valence electrons. N2O Lewis Structure - How to Draw the Lewis. Since there are no lone pairs on the atom, it is a linear structure which makes the charges cancel it. Lewis structure does NOT attempt to explain the geometry of molecules, how the bonds form, or how the electrons are shared between the atoms. Each structure explains certain properties of the molecule but not a single one of the. (When(sodium(metal(reacts(with(methanol(hydrogen(gas(evolves(from(thesolution(and(sodium. The hydrogen bonds in water-methanol mixture have been investi-gated by infrared spectroscopy of the C-O stretching band. CO(g)+2H2(g)⇌CH3OH(g) Calculate Kp for the reaction below?. 04186 g/mol. Draw the Lewis structures for the following compounds: 1) PBr3. Note that the + sign in the Lewis structure for H3O+ means that we have lost a valence electron. And that lets me know that I now have a stable Lewis structure, or a reasonable Lewis structure, because all three atoms have an octet of electrons. Because the chemical formula of Vitamin C is C6H8O6, the molecular structure is assembled as depicted in the diagrams below. now if you have an atom connected to four other atomes, keeping in mind that the electron clouds within these bonds repel each other and want to stay as far away as possible from each. Structure and reactions. Since the P forms five bonds, the Lewis structure is Here the valence shell of the phosphorus atom is said to have been expanded in order to accommodate five electron pairs. CH 3 COOH is a stronger acid because when it donates a proton, the resulting compound it forms is more stable due to delocalization of electrons. What are the geometry, shape, and bond angles of this molecule? Geometry Shape Bond Angles a) Trigonal planar Trigonal planar 120° b) Tetrahedral Tetrahedral 109. These topics will be used again in Chapter 13, Organic Chemistry. Toffeeplease. RE: Molecular geometry of CH3OH? and electron geometry?how many lone pairs on central atom? Source(s): molecular geometry ch3oh: https://tr. Lewis Structures: The Lewis structure is a simple, two-dimensional representation of a molecule in which bonds. Dimitrov , d K. RE: Molecular geometry of CH3OH? and electron geometry?how many lone pairs on central atom? Source(s): molecular geometry ch3oh: https://tr. 3 Resonance 12. Dwyane Vonda. That's because there is no simple Lewis structure for these. Clicker #2 Draw the Lewis structure for PCl3. explain why the second structure is more acidic than the first. cl lewis dot structure; h20 lewis dot structure; lewis dot diagram; boundless chemistry ch3oh dot structure; chemical bonding comparing formal charges;. 04 Lewis Structures Part 2 18:49. The Lewis structure of C2Cl4 includes a double-bonded, two-carbon chain with two chlorine atoms attached to each carbon atom. This hand drawn Lewis structure of Vitamin C depicts, atoms, valence electrons, bonds, and different bond natures. Find more Chemistry widgets in Wolfram|Alpha. CH 2 Br 2 d. 4 Lewis Symbols of the Elements (Identify lone pairs in a Lewis structure. COVID-19 campus closures: see options for getting or retaining Remote Access to subscribed content. Molecular weight calculation: 12. You could also represent the bonds as dots between the two atoms, but this may be confused with the lone pair electrons on the nitrogen. Since all the atoms are in either period 1 or 2, this molecule will adhere to the octet rule. So, the C atom will be trigonal planar with an sp2 hybridization. NOTE All the coloured pictures have java-enabled rotatable models available. Viewing Notes: In the CH 3 NH 2 Lewis structure it makes sense to write the structure as written - a Carbon atom bonded to a Nitrogen atoms with Hydrogen atoms on the outside. 1) H2S H has 1 electron in its valence shell & sulphur has 6 electron its valence shell. ; The -NH 2 part of CH 3 NH 2 is called an amine functional group. Draw a skeleton for the molecule which connects all atoms using only single bonds. Sketching out a Lewis structure gives one an idea of how the electrons in a compound are situated and give one a loose idea of the atomic structure. Be sure to use the number of available valence electrons you found earlier. Dwyane Vonda. Molecular geometry 7. NOTE All the coloured pictures have java-enabled rotatable models available. how can I draw the Lewis structure of nitrogen dioxide NO2, no2+ lewis structure, pi and, Lewis structures of NO2+ with formal charges, no2+ structure, resonance structures, how to write a lewis structure, electronegative, hcn, easy method for drawing Lewis structures of HCN, lewis structure of HCN molecule, metodo sencillo para dibujar estructuras de Lewis, methode simple pour dessiner des. Remember, this is a -1 anion, so it has an extra electron. One of the most important tools that chemists have in understanding what's going on in a chemical reaction is the Lewis structure. Browse more videos. Of these three definitions, Arrhenius is the narrowest, and Lewis is the broadest. I also go over hybridization, shape and bond angles. 2 Drawing Lewis Structures 12. The molecular geometry of CH3OH is tetrahedral at the C atom and bent at the O atom. They should also show any formal charges and unshared electrons that might be present in the molecule. 77E-010 Octanol/air (Koa) model: 1. Draw the Lewis structure for the CH 3 NH 2 (skeletal structure H 3 CNH 2). Methanol, CH3OH, is often used as a fuel in racing cars. BH 3 is acting as a Lewis acid, accepting a pair of electrons from (CH 3) 3 N to form a bond. The colorless salt can be obtained in this way: CH 3 SH + CH 3 ONa → CH 3 SNa + CH 3 OH. Boone and Douglas W. Note: The review of general chemistry in sections 1. 126K subscribers. (d) hydrogen is a small atom so the partial charge separation (polarity) of the bond is concentrated into a very small space. Question = Is CH3OH ( Methanol or methyl alcohol ) polar or nonpolar ? Answer = CH3OH ( Methanol or methyl alcohol ) is Polar What is polar and non-polar? Polar "In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. the actually is the place N has a million. CH3OH Lewis Structure: How to Draw the Lewis Structure for CH3OH. 4) Draw Lewis structure for PF3 and indicate all nonzero formal charges. 6 years ago. 6160 E-12 cm3/molecule-sec Half. Agostini eg. (a) Draw the Lewis structure for methanol, CH3OH (b) Apply VSEPR theory to determine the electron geometry around the carbon and the oxygen atoms (c) Name the types of hybridizations on both carbon and oxygen atoms (d) Sketch the molecule showing overlapping hybrid orbitals and label all bond types using the sigma, and pie notation (if any). There are four covalent bonds in the skeleton structure for SF 4. Answer Save. PACS number: 33. Therefore it is nonpolar and relatively unreactive. These hypothetical formal charges are a guide to determining the most appropriate Lewis structure. In the Lewis Structure Drawing Tool, right-click the canvas and choose get answer string. (m3/ug)): Mackay model : 1. 3) Be has 2 electrons in its valence shell & Fe has 2 electrons in its valence shell, so they make a planar structure. methanol (CH3OH) Highly flammable and poisonous type of alcohol which, when ingested even in quantities as small as 10 milliliter (two tea-spoonsful), can cause permanent blindness, and 100 milliliter may be fatal. Is it as simple as just looking these up in the periodic table and then doing lewis dot structures?. I don't understand the lewis structure. Note that the + sign in the Lewis structure for H3O+ means that we have lost a valence electron. 12 cm –1) and no magnetic long-range order. Solved • Mon Nov 12 2018 12:41:02 GMT-0500 (EST) Lewis Dot Structure. 🤓 Based on our data, we think this question is relevant for Professor Demoin's class at UARK. Note that the + sign in the Lewis structure for H3O+ means that we have lost a valence electron. In simple molecules, the atom with the most available sites for bondng is usually placed central. Draw all of the possible resonance structures for the following ions or molecules: 1) nitrate ion: 2) formate ion (CHO2-1): 3) cyclobutadiene (C4H4): 4) ozone (O3): VSEPR Worksheet. Molecular polarity HCO 2-1 1. A tetrahedral shape will be formed. Lewis sit structure of CH3OH. Today we are going to go through the Lewis structure of I3- or also know as Triodide ion as it has a negative charge on it. This structure contains 2 lone pair of electrons on oxygen (highlighted red). 4, but is about a million times more acidic than methanol. 04 Lewis Structures Part 2 18:49. Structure Conjugate Base H The alkane is less acidic than the second structure because its conjugate base is less stabilized, with no resonance structures. Step 1: Find valence e- for all atoms. Different atoms are bonded together to chemically compose the structure of Vitamin C. Which of these is the correct Lewis structure for nitrogen tri-iodide, NI3? Which of these is the correct Lewis structure for a diatomic fluorine molecule, F2?. Ionic compounds do not involve sharing of electrons between bonding pairs unlike molecules. Each structure explains certain properties of the molecule but not a single one of the. DRAWING LEWIS STRUCTURES. the actually is the place N has a million. Molar mass of CH3OH = 32. Become a Patron! ChemiDay you always could choose go nuts or keep calm with us or without. Group Assignment 1 key - Group Assignment 1 Question 1 Which of the following is the correct Lewis structure for CH3OH A B C Question 2 Which of the. Methyl Alcohol (CH3OH) More detailed information. In this interactive and animated object, students distribute the valence electrons in simple covalent molecules with one central atom. Structure: Lewis Structure: Comments: alcohol: CH 3 OH: methyl alcohol: In methyl alcohol, or methanol the red atom is an oxygen. 2) Si has 4 electrons its valence shell & Cl need only 1 electron to complete its octet, therefore 4 Cl will make 4 bonds. Draw the Lewis structure for the molecule or ion. Remember that Lewis dot structures are drawn for covalent (molecular) compounds that share electrons. Convert grams CH3OH to moles or moles CH3OH to grams. Molecular Structure (Cont. ; In the Lewis structure for CH 3 NH 2 there are a total of 14 valence electrons. ethanol + butanoic acid ethyl butanoate + water. Lewis Structure| Dot Structure of NO2 A simple procedure for writing Dot Electron Structures was given in a previous article entitled “Lewis Structures and the Octet Rule”. I also go over hybridization, shape, sigma, pi bonding and bond angles. Since the molecule is linear, it has 180 degree bond angles. How to draw Lewis Diagrams. (a) Draw the Lewis structure for methanol, CH3OH (b) Apply VSEPR theory to determine the electron geometry around the carbon and the oxygen atoms (c) Name the types of hybridizations on both carbon and oxygen atoms (d) Sketch the molecule showing overlapping hybrid orbitals and label all bond types using the sigma, and pie notation (if any). Methanol, also known as methyl alcohol amongst other names, is a chemical with the formula C H 3 O H (a methyl group linked to a hydroxyl group, often abbreviated MeOH). At each end, the chlorine atoms are spaced approximately 120 degrees from each other and from the carbon atom. 126K subscribers. PubChem Substance ID 57648672. The Lewis-base adducts all display very weak antiferromagnetic coupling (J ≈ –0. polar covalent bonding. Most resonance structures and coordination compounds are also supported. Browse more videos. Species Elecronegativity difference in bond Bond Polarity Mp NCl 3 ∆E = 3. A planar structure will be formed. The sketched 3D structural formula of methane (on the left) may be understood even more clearly by comparison with the ('ball and stick') model of the 3D structure of methane (on the right). 2 Names and Identifiers. D) Lewis structures are drawn for molecules and not typically for ionic compounds. If you are not sure if your structure is correct, do a formal charge check. 1) H2S H has 1 electron in its valence shell & sulphur has 6 electron its valence shell. Electronic geometry and ideal bond angles 6. CH3OH + HCl --> CH3Cl + H2O Reaction type ?. Thermo Unit Reaction Enthalpies 1. As a general rule, covalent bonds are formed between elements lying toward the right in the periodic table (i. 7915 g/mL, is required to produce exactly 1000 kg of MTBE, assuming a 100% yield? Write two complete balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures. Since oxygen atoms are much more electronegative than hydrogen atoms, the. Favourite answer. Structure–reactivity relationship in Co 3 O 4 promoted Au/CeO 2 catalysts for the CH 3 OH oxidation reaction revealed by in situ FTIR and operando EXAFS studies† M. Molecular weight calculation: 12. If you look at the Lewis structure for CH3OH it does not appear a symmetrical molecule. 2) to calculate the energy changes associated with each of these reactions. Dipole-dipole forces require that the molecules have a permanent dipole moment, so determine the shape of each molecule (draw a Lewis structure, then use VSEPR theory) and see if the shape allows a permanent dipole moment. 8% Synonym: Methyl alcohol. The Lewis structure of ammonia, #NH_3#, would be three hydrogen atoms bonded to a nitrogen atom in the middle, with a lone pair of electrons on top of the atom. All structures follow the octet rule. Drawing the Lewis Structure for CH 3 NH 2. In this example, we can draw two Lewis structures that are energetically equivalent to each other — that is, they have the same types of bonds, and the same types of formal charges on all of the structures. Molecular geometry 7. Tabakova , c C. This Site Might Help You. 4E-009 Mackay model : 1. What is the Lewis dot structure for the HYDRIDE ion? A)H:- B)H+ C)H' D)H3O+ E)none It's hard for me to read the dots but I THINK answer a) looks like this?. (((((The inductive (polarity) effect is responsible for the pK a difference. Viewing Notes: For the CH 3 OH Lewis structure there are a total of 20 valence electrons available. Remember, this is a -1 anion, so it has an extra electron. The octet rule is a bonding theory used to predict the molecular structure of covalently bonded molecules. Structural Formula. C:4×2=8 H:1×6=6 O:6. ; In the Lewis structure for CH 3 NH 2 there are a total of 14 valence electrons. Resonance. Structure and reactions. 7915 g/mL, is required to produce exactly 1000 kg of MTBE, assuming a 100% yield? Write two complete balanced equations for each of the following reactions, one using condensed formulas and one using Lewis structures. 5°, and a tetrahedral. CH3OH Lewis Structure: How to Draw the Lewis Structure for CH3OH A step-by-step explanation of how to draw the CH3OH Lewis Structure. CH3OH synonyms, CH3OH pronunciation, CH3OH translation, English dictionary definition of CH3OH. Intermolecular forces Electrostatics The attraction of a positive charge with a negative charge is the force that allows for the structure of the atom, causes atoms to stick together to form molecules; both ionic and covalent, and ultimately is responsible for the formation of liquids, solids and solutions. C2H4 H2 22. According to the Lewis electron-dot diagram, two resonance structures are. Add them together. The geometric structure or shape of the CH3OH molecule which has 2 geometric centers around the carbon and oxygen atoms is tetrahedral around the carbon to 3 hydrogen and oxygen bonded atoms with a bent tetrahedral around the oxygen atom with its 2 lone pairs and oxygen to carbon and hydrogen, bonded atoms. Draw the Lewis structure for nitric acid (the hydrogen atom is attached to one of the oxygen atoms). php(143) : runtime-created function(1) : eval()'d code(156) : runtime-created. (m3/ug)): Mackay model : 1. Structure of POLYMERS - covalent bonding in large molecules i. View CHE 230 Study-HMWK from CHE 230 at University of Kentucky. Now another way we can show this, now that we've established what our octet. In a Lewis structure, formal charges can be assigned to each atom by treating each bond as if one-half of the electrons are assigned to each atom. CH3OH is the same. Perspective drawing 3. Electronic geometry and ideal bond angles 6. directions as shown in Figure 6 then the molecule is considered nonpolar, but if the polar bonds align, or do not cancel out then there is a net dipole and we consider the molecule to be dipolar as shown in Figure 6. This problem has been solved! See the answer. The ability to draw a correct Lewis structure can depend on how information is presented: more than 90% of the group were able to draw the structure for methanol when given the condensed formula (CH3OH), but only around 60% could when given the molecular formula (CH4O). Become a Patron! ChemiDay you always could choose go nuts or keep calm with us or without. The structure of the organic compound contains a total of 20 valence electrons. Water, H 2 O Lewis and Three-Dimensional Structures. You should consult the Lewis structure rules and a periodic table while doing this exercise. This is the reason why ammonia acts as a Lewis base, as it can donate those electrons. Lamberti , bf D. In the lewis structure of CH3OH, how many lone pairs of electrons are there? 2. 5°, and a tetrahedral. Example Lewis Structure: Formaldehyde, CH 2O The TOTAL number of valence electrons the atoms bring with them to the molecule: 1 carbon atom with 4 valence electrons 4 2 hydrogen atoms, each with 1 valence electron 2(1) 1 oxygen atom with 6 valence electrons 6 Total available electrons 12. A wedge and dash projection (sometimes spelled wedge-and-dash) is a drawing, a means of representing a molecule in which three types of lines are used in order. 3 Resonance 12. This demo will convert a skeletal figure, provided by a drawing in the HTML5 SketcherCanvas component on the left, into a Lewis Dot Structure in the Canvas on the right. The resulting thiolate anion is a strong nucleophile. Certificate of Analysis (COA) Specification Sheet (PDF) Similar Products. 3-There are three H atoms surround the C atom. Solution for CH3OH(g) + HI(g) CH3I(g) + H2O(g)draw Lewis structures for all reactant and product molecules. The circles are drawn to represent the octet for each atom. Starting with a structure indicating only atom connections (single bonds), you can practice constructing a Lewis dot structure. 8 years ago. To avoid this, cancel and sign in to YouTube on your computer. A Brønsted-Lowry acid is a proton donor. How to draw Lewis Diagrams. Structure, properties, spectra, suppliers and links for: methoxide. The geometric structure or shape of the CH3OH molecule which has 2 geometric centers around the carbon and oxygen atoms is tetrahedral around the carbon to 3 hydrogen and oxygen bonded atoms with a bent tetrahedral around the oxygen atom with its 2 lone pairs and oxygen to carbon and hydrogen, bonded atoms. Solved • Mon Nov 12 2018 12:41:02 GMT-0500 (EST). A Lewis structure for molecular compounds is a 2D representation in which electrons that are shared between two atoms are represented as a single line connecting the atoms. Content is available under CC BY-SA 3. Follow these simple steps to correctly draw a Lewis dot structure: Add up the total number of valence electrons found …. 4E-009 Mackay model : 1. A CCL4 Lewis structure is a diagram that represents the electron configuration of covalently bonded compounds. Structural Formula. The molecule methanol (methyl alcohol) has the structure CH3OH, and contains fourteen valence electrons (four for carbon, six for oxygen, one each for the four hydrogens). 6) There are nine possible stereoisomers of 1,2,3,4,5,6-hexachlorocyclohexane. For example, the Lewis structure for the. the actually is the place N has a million. Examples: carbon in methane: FC = 4 - 0 - 8/2 = 0. The only way I can draw the Lewis structure with a double bond and a formal charge of +1 on the nitrogen (and 0 on the oxygen) violates the octet rule. Chem 140- chapter 9. 5) Draw Lewis structure for CHO2^1- and indicate all nonzero formal charges. In CH3OH the sharing is not equal and there is a net dipole. How do you draw the Lewis Structure for SO4,SF6,NH3 and H2S. Step 1: Draw the Lewis structure, Step 2: Draw the 3D molecular structure w/ VSEPR rules, Step 3: Use symmetry to determine if the molecule is polar or non-polar. Draw a skeleton structure. Resonance stabilizes the conjugate base of the alkene structure, as it spreads out the negative charge (and the pi bond). When you see a carbon with an OH attached (like CH3OH, C2H5OH, etc. This set index page lists chemical structure articles associated with the same molecular formula. Resonance is a phenomenon where a molecule or an ion can be represented in more than one Lewis dot structure. As a general rule, covalent bonds are formed between elements lying toward the right in the periodic table (i. Petrucci: Section 10-7. Carbon dioxide is CO2. Click here to view a Jmol structure of methanol. , molecules where nonmetal atoms are held together because they share one or more pairs of electrons. Which of the following is the correct Lewis structure for phosphorus tribromide, PBr 3? Which of the following is the correct Lewis structure for ethene (ethylene), C 2 H 4 ? Which of the following elements will NOT be surrounded by an octet of electrons in a correctly drawn Lewis structure?. Categories Public Domain Tutorial. CH3OH is the same. Make sure you have the latest version of Java installed and that it is enabled on your browser. Convert grams CH3OH to moles or moles CH3OH to grams. P2o5 Lewis Structure - More information - Djekova Items where Year is 2007 P2o5 Lewis Structure: pin. Drawing the Lewis Structure for CH 3 NH 2. C:8x2=16 H:2x6=12 O:8 T. Hit Return to see all results Lewis Dot Structure are those structures in which the electrons are represented by the dots and the bonds between the Want to see the full answer? See Solution. 12 cm –1) and no magnetic long-range order. The molecular geometry of CH3OH is tetrahedral at the C atom and bent at the O atom. In CH3OH the sharing is not equal and there is a net dipole. Most resonance structures and coordination compounds are also supported. She has taught science courses at the high school, college, and graduate levels. 6 Determining Lewis Structures (Draw Lewis structures. Total = 20. In the Lewis Structure Drawing Tool, right-click the canvas and choose get answer string. The geometric structure or shape of the CH3OH molecule which has 2 geometric centers around the carbon and oxygen atoms is tetrahedral around the carbon to 3 hydrogen and oxygen bonded atoms with a bent tetrahedral around the oxygen atom with its 2 lone pairs and oxygen to carbon and hydrogen, bonded atoms. Of these three definitions, Arrhenius is the narrowest, and Lewis is the broadest. Helmenstine holds a Ph. If multiple pairs of electrons are shared they are represented by multiple lines between the atoms. Lewis Dot Structure Generator. Using the polarity arrow indicate your prediction of the bond dipole in iodine monochloride. lewis dot structure for h3coh lewis dot structure for h3coh How do you draw Lewis dot structure for H3COH Imagechef app for blackberry Star wars mandalorian names Brandy. 2) to calculate the energy changes associated with each of these reactions. Petrucci: Section 10-7. CO(g)+2H2(g)⇌CH3OH(g) Calculate Kp for the reaction below?. 1) Draw Lewis structure for N2H2 and indicate all nonzero formal charges. (a) Draw the Lewis structure for methanol, CH3OH (b) Apply VSEPR theory to determine the electron geometry around the carbon and the oxygen atoms (c) Name the types of hybridizations on both carbon and oxygen atoms (d) Sketch the molecule showing overlapping hybrid orbitals and label all bond types using the sigma, and pie notation (if any). Use formal charge to determine which of the resonance structures is most important to the structure of nitric acid. April 27, 2017 Timtech 5 Comments. The structure with three double bonds was proposed by Kekule as an attempt to explain how a molecule whose molecular formula was C 6 H 6 could be built out of carbons which make four bonds. Structure Conjugate Base H The alkane is less acidic than the second structure because its conjugate base is less stabilized, with no resonance structures. The strength of this interaction, while not quite as strong as a covalent bond,. 3) Be has 2 electrons in its valence shell & Fe has 2 electrons in its valence shell, so they make a planar structure. So, total valence electrons are 16. For example, for NO 2-the number of valence electrons is 5 + 2 (6) + 1 = 18 e-(or 9 pairs), and we find that there are two equally valid Lewis structures that can be drawn:. Dans leur procédé d’embaumement, les anciens Égyptiens utilisaient un grand nombre de substances, y compris le méthanol, obtenu par pyrolyse du bois. Lewis Structures, Shapes, and Polarity W 319 Everett Community College Student Support Services Program Draw Lewis structures, name shapes and indicate polar or non-polar for the following molecules: a. 4, but is about a million times more acidic than methanol. Get the free "Lewis structure" widget for your website, blog, Wordpress, Blogger, or iGoogle. Lamberti , bf D. You should put an equilibrium sign in the middle too. Usually the electronegative atom is oxygen, nitrogen, or fluorine, which has a partial negative charge. Lewis structures are meant to provide a visualization of the atomic structure and the distribution of electrons in a given chemical compound. 1e: Deduce the Lewis (electron dot) structure of ethanedioic acid, HOOC−COOH. The former, known as a 'Lewis dot diagram,' indicates a pair of shared electrons between the atomic symbols, while the latter, known as a 'Lewis structure,' uses a dash to indicate the pair of shared electrons that form a covalent bond. Cependant le méthanol pur n’a été isolé pour la première fois qu’en 1661 par Robert Boyle, qui lui donna le nom d’esprit de bois, parce qu'il était produit par la distillation, ou pyrolyse du. The first structure is the most important (it contributes the It has octet for C and O and no formal It also has one bond more than other. This demo will convert a skeletal figure, provided by a drawing in the HTML5 SketcherCanvas component on the left, into a Lewis Dot Structure in the Canvas on the right. Lewis Structures: The Lewis structure is a simple, two-dimensional representation of a molecule in which bonds. These structures provide information about the types of bonds (single, double, or triple) as well as the connectivity of atoms. Ea 1 Introduction Water [1] as well as methanol [2] is a continuum random network of hydrogen bonds, which determines the special physical structure of both liquids. The geometric structure or shape of the CH3OH molecule which has 2 geometric centers around the carbon and oxygen atoms is tetrahedral around the carbon to 3 hydrogen and oxygen bonded atoms with a bent tetrahedral around the oxygen atom with its 2 lone pairs and oxygen to carbon and hydrogen, bonded atoms. Homework Statement Use the bond energies (in Table 4. Readings for this section. Molecular geometry 7. You could also represent the bonds as dots between the two atoms, but this may be confused with the lone pair electrons on the nitrogen. 126K subscribers. BH 3 is acting as a Lewis acid, accepting a pair of electrons from (CH 3) 3 N to form a bond. in biomedical sciences and is a science writer, educator, and consultant. It is the simplest and most limited theory on electronic structure. Step 1: Draw the Lewis structure. If an internal link led you here, you may wish to change the link to point directly to the intended article. For molecules or ions with three or more bonded atoms, the Lewis structure indicates which specific atoms are bonded together and the number of bonds between the atoms. A planar structure will be formed. 6160 E-12 cm3/molecule-sec Half. so intermolecular forces will exist as polar-polar. There are four covalent bonds in the skeleton structure for SF 4. A Double Bond is a covalent bond in which four electrons (two pairs) are shared by the bonding atoms. Resonance is a phenomenon where a molecule or an ion can be represented in more than one Lewis dot structure. For the CH3OH Lewis structure, calculate the total number of valence electrons for the CH3OH molecule. Record and check the correct answers for the remaining structures Lewis Structure Molecule 1. Video Rating: 5 / 5. Lewis Dot of Methylamine. Electronic configuration of oxygen is, Oxygen = 8 = 1s², 2s², 2px², 2py¹, 2pz¹. Problem Details. I also go over hybridization, shape, sigma, pi bonding and bond angles. 5 degrees), and oxygen has two lone pairs. So, the C atom will be trigonal planar with an sp2 hybridization. 2) Si has 4 electrons its valence shell & Cl need only 1 electron to complete its octet, therefore 4 Cl will make 4 bonds. How many neutrons does the most common isotope of Uranium have? Q: A compound, ##XF_5##, is 42. The Lewis formalism used for the H 2 molecule is H:H or H—H. In simple molecules, the atom with the most available sites for bondng is usually placed central. 1021/om401118n, 33, 1, (387-393), (2013). yet you additionally can draw it as O-N=O. u1y1m75kfv, wqmq0t0bwj, fcpv58txnm33l4f, c4gd2ia3xulrje, 5hg7bzb06tkoq, 47ol38ggson, wa8sttl9tvb, 0enw0tzysycwxhn, z9n0rbhlvjdrp5w, lwnz7ldai8, pbc7laqufzj2fb, uqrwl9647ps, e8qn4bpd2pqpwuk, g2uake6324f, bww6mzm49oa, 0l6yq5ihq4zt2u, gejzk9wieh2he, r45b2h6p3n7p0lj, jzp4h1bxyxybqio, 9a1obgyquu0o, 8ix5qak8dsbnqx, 5l2ldhk4dfvw6u4, 5m96piwrgpav8, osh4ie3wf9, 2nik5gokc1kkpi, td867xjchxcxl, ubh2a68tewsr40v, ir17blmpquz, m6mpzlzevogfl, 2iqtyd7pqp3, katawy27nsjy4o1, 9lnxpfxk8s, jipfmddtp44 | 2020-05-30 18:06:08 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5029885768890381, "perplexity": 2927.771716360446}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-24/segments/1590347410284.51/warc/CC-MAIN-20200530165307-20200530195307-00564.warc.gz"} |
http://adv-math.com/category/2017/ | ### Browsed byCategory: 2017
Tibebu Worku Hunde, Mengistu Goa Sangago and Habtu Zegeye, Approximation of a Common Fixed Point of a Family of $G$-Nonexpansive Mappings in Banach Spaces with a Graph, Volume 2017, Number 6, Pages 137-152, 2017
## Tibebu Worku Hunde, Mengistu Goa Sangago and Habtu Zegeye, Approximation of a Common Fixed Point of a Family of $G$-Nonexpansive Mappings in Banach Spaces with a Graph, Volume 2017, Number 6, Pages 137-152, 2017
Abstract: In this paper, we introduce an explicit iterative scheme for approximating common fixed points for a finite family of $G$-nonexpansive mappings in a uniformly convex Banach space with a directed graph. Our results extend and improve the results of [Tripak, O.: Common fixed points of...
M.A. Barakat, M.A. Ahmed and A.M. Zidan, Weak Quasi-Partial Metric Spaces and Fixed Point Results, Volume 2017, Number 6, Pages 123-136, 2017
## M.A. Barakat, M.A. Ahmed and A.M. Zidan, Weak Quasi-Partial Metric Spaces and Fixed Point Results, Volume 2017, Number 6, Pages 123-136, 2017
Abstract: In the present paper, we introduce a new generalized type of quasi-partial metric spaces so-called weak quasi-partial metric spaces. This concept is a generalization and unification of weak partial metric spaces and quasi-partial metric spaces. Also, some fixed point theorems in these spaces are given....
Ioannis K. Argyros and Santhosh George, Ball Convergence of the Laguerre-Like Method for Multiple Zeros, Volume 2017, Number 6, Pages 114-122, 2017
## Ioannis K. Argyros and Santhosh George, Ball Convergence of the Laguerre-Like Method for Multiple Zeros, Volume 2017, Number 6, Pages 114-122, 2017
Abstract: The aim of this paper is to present a ball convergence of the Laguerre- like method for zeros of multiplicity under weak convergence conditions. Key words: Laguerre-like method, multiple zeros, ball convergence. DOWNLOAD PDF DOWNLOAD XML How to cite this...
Waggas Galib Atshan and Ihsan Ali Abbas, Some Properties of Differential Sandwich Results of $p$-valent Functions Defined by Liu-Srivastava Operator, Volume 2017, Number 6, Pages 101-113, 2017
## Waggas Galib Atshan and Ihsan Ali Abbas, Some Properties of Differential Sandwich Results of $p$-valent Functions Defined by Liu-Srivastava Operator, Volume 2017, Number 6, Pages 101-113, 2017
Abstract: In this paper, we obtain some results of differential subordination and superordination for p-valent function in the open unit disk involving operator. Also we derive some sandwich theorems. Key words: Subordination, Superordination, Multivalent function, Hardamard product, Generalized hypergeometric function, Ruscheweyh derivative. DOWNLOAD PDF ...
D.Stephen Dinagar and U.Hari Narayanan, A Study on Rank of Hexagonal Fuzzy Number Matrices, Volume 2017, Number 6, Pages 82-100, 2017
## D.Stephen Dinagar and U.Hari Narayanan, A Study on Rank of Hexagonal Fuzzy Number Matrices, Volume 2017, Number 6, Pages 82-100, 2017
Abstract: A hexagonal fuzzy matrix has various type of ranks that is, row rank, column rank, fuzzy rank and fuzzy full rank. In this article, some methods are described to find these types of ranks for Hexagonal fuzzy matrices (HFMs) and investigated the relationship between them...
A. M. Abd El-Latif and Rodyna A. Hosny, Supra Open Soft Sets and Associated Soft Separation Axioms, Volume 2017, Number 6, Pages 68-81, 2017
## A. M. Abd El-Latif and Rodyna A. Hosny, Supra Open Soft Sets and Associated Soft Separation Axioms, Volume 2017, Number 6, Pages 68-81, 2017
Abstract: In this paper, we introduce and investigate some weak soft separation axioms by using the notion of supra open soft sets, which is a generalization of the soft (resp. semi soft, pre soft, $\alpha$-soft and $\beta$-soft separation axioms. We study the relationships between these new...
Mandeep Kumari and Renu Chugh, Dynamics of Superior Anti-fractals in a New Orbit, Volume 2017, Number 6, Pages 60-67, 2017
## Mandeep Kumari and Renu Chugh, Dynamics of Superior Anti-fractals in a New Orbit, Volume 2017, Number 6, Pages 60-67, 2017
Abstract: Anti-fractals have interesting features in the complex graphics of dynamical system. The aim of this paper is to visualize Superior tricorns and multicorns using a new iteration introduced by M. Abbas et al.[8] and study the pattern among the anti-fractals in the complex dynamics of...
Bazuaye Frank E and Ajibola S. O, A Two-Step Seventh-Order Extended Exponential General Linear Methods for Solving IVPs in ODEs, Volume 2017, Number 6, Pages 51-59, 2017
## Bazuaye Frank E and Ajibola S. O, A Two-Step Seventh-Order Extended Exponential General Linear Methods for Solving IVPs in ODEs, Volume 2017, Number 6, Pages 51-59, 2017
Abstract: In this paper, a class of extended exponential general linear methods of second stage seventh order is developed. The resulting integrator is based on the variation of constant formula for initial value problems (IVPs) in Ordinary differential equations (ODEs). Stability analysis indicate that the scheme...
M.Raafat and A.M.Abd El-Latif, On Multi Weak Structures, Volume 2017, Number 6, Pages 42-50, 2017
## M.Raafat and A.M.Abd El-Latif, On Multi Weak Structures, Volume 2017, Number 6, Pages 42-50, 2017
Abstract: In this paper, the concept of multi weak structures is introduced and its several results are presented in details. It is worth mentioning that multi weak structures are a generalization of weak structures and multi topological spaces. Moreover, we give the deviations between the previous...
Ziad Rached, An Exact Method for a Class of Third Order Nonlinear Differential Equations, Volume 2017, Number 6, Pages 36-41, 2017
## Ziad Rached, An Exact Method for a Class of Third Order Nonlinear Differential Equations, Volume 2017, Number 6, Pages 36-41, 2017
Abstract: In this work, an existing method for solving certain classes of nonlinear second order ordinary differential equations is extended to nonlinear third order ordinary differential equations. The method simply expresses the solution of the nonlinear differential equation in terms of solutions of an equivalent... | 2017-11-19 05:05:39 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5883034467697144, "perplexity": 2870.4658699507645}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-47/segments/1510934805362.48/warc/CC-MAIN-20171119042717-20171119062717-00483.warc.gz"} |
https://zbmath.org/serials/?q=se%3A7300 | ## Theory of Computing
Short Title: Theory Comput. Publisher: University of Chicago, Department of Computer Science, Chicago, IL ISSN: 1557-2862/e Online: http://theoryofcomputing.org/articles/main/index.html Comments: Indexed cover-to-cover; Published electronic only as of Vol. 1 (2005). This journal is available open access.
Documents Indexed: 302 Publications (since 2005) References Indexed: 190 Publications with 6,028 References.
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### Latest Issues
18 (2022) 17 (2021) 16 (2020) 15 (2019) 14 (2018) 13 (2017) 12 (2016) 11 (2015) 10 (2014) 9 (2013) 8 (2012) 7 (2011) 6 (2010) 5 (2009) 4 (2008) 3 (2007) 2 (2006) 1 (2005)
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### Authors
9 Aaronson, Scott 9 Lovett, Shachar 8 Wigderson, Avi 7 Dvir, Zeev 7 Servedio, Rocco A. 6 Bansal, Nikhil 6 Håstad, Johan Torkel 6 O’Donnell, Ryan 6 Srinivasan, Srikanth 5 Guruswami, Venkatesan 5 Khot, Subhash Ajit 5 Mossel, Elchanan 5 Regev, Oded 5 Sherstov, Alexander A. 5 Shpilka, Amir 5 Vadhan, Salil P. 5 Viola, Emanuele 4 Ambainis, Andris 4 Chekuri, Chandra S. 4 Feige, Uriel 4 Hrubeš, Pavel 4 Kopparty, Swastik 4 Sudan, Madhu 4 Williams, Richard Ryan 3 Alon, Noga M. 3 Austrin, Per 3 Blum, Avrim L. 3 Briët, Jop 3 Bun, Mark 3 Chakrabarty, Deeparnab 3 Dadush, Daniel 3 De, Anindya K. 3 Göös, Mika 3 Harsha, Prahladh 3 Huang, Sangxia 3 Krauthgamer, Robert 3 Kumar, Mrinal 3 Kuperberg, Gregory John 3 Makarychev, Yury S. 3 Manokaran, Rajsekar 3 Pitassi, Toniann 3 Raz, Ran 3 Ron-Zewi, Noga 3 Saks, Michael E. 3 Špalek, Robert 3 Srinivasan, Aravind 3 Svensson, Ola 3 Ta-Shma, Amnon 3 Tan, Liyang 3 Thaler, Justin 3 Trevisan, Luca 3 Wan, Andrew 3 Yehudayoff, Amir 3 Zhang, Shengyu 2 Ajtai, Miklós 2 Allender, Eric W. 2 Arora, Sanjeev 2 Balcan, Maria-Florina 2 Beigi, Salman 2 Ben-Aroya, Avraham 2 Ben-Sasson, Eli 2 Bhangale, Amey 2 Blais, Eric 2 Braverman, Mark 2 Canonne, Clement Louis 2 Childs, Andrew M. 2 Chlamtac, Eden 2 Chuzhoy, Julia 2 Dasgupta, Anirban 2 Diakonikolas, Ilias 2 Drucker, Andrew 2 Fefferman, Bill 2 Filmus, Yuval 2 Fischer, Eldar 2 Forbes, Michael A. 2 Fortnow, Lance J. 2 Garg, Shashwat 2 Gavinsky, Dmitry 2 Goyal, Navin 2 Guo, Siyao 2 Gupta, Anupam 2 Haramaty, Elad 2 Haviv, Ishay 2 Holenstein, Thomas 2 Jain, Rahul 2 Kamath, Pritish 2 Khanna, Sanjeev 2 Klivans, Adam R. 2 Kothari, Robin 2 Landsberg, Joseph Montague 2 Lee, Chin Ho 2 Lee, Euiwoong 2 Lee, Homin K. 2 Limaye, Nutan 2 Magen, Avner 2 Meka, Raghu 2 Micciancio, Daniele 2 Motwani, Rajeev 2 Murtagh, Jack 2 Nagarajan, Viswanath ...and 370 more Authors
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### Fields
283 Computer science (68-XX) 46 Information and communication theory, circuits (94-XX) 34 Combinatorics (05-XX) 32 Operations research, mathematical programming (90-XX) 31 Quantum theory (81-XX) 16 Number theory (11-XX) 15 Probability theory and stochastic processes (60-XX) 15 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 14 Mathematical logic and foundations (03-XX) 12 General and overarching topics; collections (00-XX) 10 Linear and multilinear algebra; matrix theory (15-XX) 9 Order, lattices, ordered algebraic structures (06-XX) 8 Convex and discrete geometry (52-XX) 6 Numerical analysis (65-XX) 4 Field theory and polynomials (12-XX) 4 Group theory and generalizations (20-XX) 4 Harmonic analysis on Euclidean spaces (42-XX) 4 Statistics (62-XX) 2 History and biography (01-XX) 1 Commutative algebra (13-XX) 1 Algebraic geometry (14-XX) 1 Associative rings and algebras (16-XX) 1 Real functions (26-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Approximations and expansions (41-XX) 1 Functional analysis (46-XX) 1 Differential geometry (53-XX) 1 Manifolds and cell complexes (57-XX) 1 Optics, electromagnetic theory (78-XX)
### Citations contained in zbMATH Open
209 Publications have been cited 1,668 times in 1,477 Documents Cited by Year
Maximizing the spread of influence through a social network. Zbl 1337.91069
Kempe, David; Kleinberg, Jon; Tardos, Éva
2015
Linear degree extractors and the inapproximability of max clique and chromatic number. Zbl 1213.68322
Zuckerman, David
2007
The multiplicative weights update method: a meta-algorithm and applications. Zbl 1283.68414
Arora, Sanjeev; Hazan, Elad; Kale, Satyen
2012
A quantum algorithm for the Hamiltonian NAND tree. Zbl 1213.68284
Farhi, Edward; Goldstone, Jeffrey; Gutmann, Sam
2008
Can you beat treewidth? Zbl 1213.68316
Marx, Dániel
2010
Approximate nearest neighbor: towards removing the curse of dimensionality. Zbl 1278.68344
Har-Peled, Sariel; Indyk, Piotr; Motwani, Rajeev
2012
New lower bounds for the border rank of matrix multiplication. Zbl 1336.68102
Landsberg, Joseph M.; Ottaviani, Giorgio
2015
Polynomial degree and lower bounds in quantum complexity: collision and element distinctness with small range. Zbl 1213.68281
Ambainis, Andris
2005
Inapproximability of vertex cover and independent set in bounded degree graphs. Zbl 1243.68183
Austrin, Per; Khot, Subhash; Safra, Muli
2011
The computational complexity of linear optics. Zbl 1298.81046
Aaronson, Scott; Arkhipov, Alex
2013
Quantum search of spatial regions. Zbl 1213.68279
Aaronson, Scott; Ambainis, Andris
2005
An $$O(\sqrt{n})$$ approximation and integrality gap for disjoint paths and unsplittable flow. Zbl 1213.68700
Chekuri, Chandra; Khanna, Sanjeev; Shepherd, F. Bruce
2006
Near-optimal network design with selfish agents. Zbl 1213.68698
Anshelevich, Elliot; Dasgupta, Anirban; Tardos, Éva; Wexler, Tom
2008
The projection games conjecture and the NP-hardness of $$\ln n$$-approximating Set-Cover. Zbl 1335.68097
Moshkovitz, Dana
2015
Rank bounds and integrality gaps for cutting planes procedures. Zbl 1213.68328
Buresh-Oppenheim, Joshua; Galesi, Nicola; Hoory, Shlomo; Magen, Avner; Pitassi, Toniann
2006
Separation of multilinear circuit and formula size. Zbl 1213.68301
Raz, Ran
2006
Approximation algorithms and online mechanisms for item pricing. Zbl 1213.68699
Balcan, Maria-Florina; Blum, Avrim
2007
Proving integrality gaps without knowing the linear program. Zbl 1213.68306
Arora, Sanjeev; Bollobás, Béla; Lovász, László; Tourlakis, Iannis
2006
Near-optimal and explicit Bell inequality violations. Zbl 1298.81034
Buhrman, Harry; Regev, Oded; Scarpa, Giannicola; de Wolf, Ronald
2012
Distance transforms of sampled functions. Zbl 1280.68266
Felzenszwalb, Pedro F.; Huttenlocher, Daniel P.
2012
Correlation clustering with a fixed number of clusters. Zbl 1213.68704
Giotis, Ioannis; Guruswami, Venkatesan
2006
Norms, XOR lemmas, and lower bounds for polynomials and protocols. Zbl 1213.68321
Viola, Emanuele; Wigderson, Avi
2008
How hard is it to approximate the Jones polynomial? Zbl 1337.68109
Kuperberg, Greg
2015
Computing the partition function for cliques in a graph. Zbl 1351.05212
Barvinok, Alexander
2015
Matrix approximation and projective clustering via volume sampling. Zbl 1213.68702
Deshpande, Amit; Rademacher, Luis; Vempala, Santosh; Wang, Grant
2006
Elusive functions and lower bounds for arithmetic circuits. Zbl 1213.68318
Raz, Ran
2010
A separation of NP and conp in multiparty communication complexity. Zbl 1213.68293
Gavinsky, Dmitry; Sherstov, Alexander A.
2010
Locally checkable proofs in distributed computing. Zbl 1401.68085
Göös, Mika; Suomela, Jukka
2016
Limitations of quantum advice and one-way communication. Zbl 1213.68278
Aaronson, Scott
2005
Derandomizing the Ahlswede-Winter matrix-valued Chernoff bound using pessimistic estimators, and applications. Zbl 1213.68697
Wigderson, Avi; Xiao, David
2008
The communication complexity of gap Hamming distance. Zbl 1253.68158
Sherstov, Alexander A.
2012
Matchgates revisited. Zbl 1342.68156
Cai, Jin-Yi; Gorenstein, Aaron
2014
Grothendieck inequalities for semidefinite programs with rank constraint. Zbl 1297.68261
Briët, Jop; de Oliveira Filho, Fernando Mário; Vallentin, Frank
2014
Query efficient PCPs with perfect completeness. Zbl 1213.68331
2005
An exponential separation between regular and general resolution. Zbl 1213.68303
Alekhnovich, Michael; Johannsen, Jan; Pitassi, Toniann; Urquhart, Alasdair
2007
Parallel repetition: simplification and the no-signaling case. Zbl 1213.68297
Holenstein, Thomas
2009
The submodular welfare problem with demand queries. Zbl 1213.68703
Feige, Uriel; Vondrák, Jan
2010
The need for structure in quantum speedups. Zbl 1298.81045
Aaronson, Scott; Ambainis, Andris
2014
Quantum lower bound for the collision problem with small range. Zbl 1213.68286
Kutin, Samuel
2005
Quantum fan-out is powerful. Zbl 1213.68298
Høyer, Peter; Špalek, Robert
2005
The randomized communication complexity of set disjointness. Zbl 1213.68332
2007
The power of unentanglement. Zbl 1213.68280
Aaronson, Scott; Beigi, Salman; Drucker, Andrew; Fefferman, Bill; Shor, Peter
2009
Quantum expanders: motivation and construction. Zbl 1213.81052
Ben-Aroya, Avraham; Schwartz, Oded; Ta-Shma, Amnon
2010
Regularity lemmas and combinatorial algorithms. Zbl 1253.68162
Bansal, Nikhil; Williams, Ryan
2012
List-decoding multiplicity codes. Zbl 1397.94127
Kopparty, Swastik
2015
An optimal lower bound for monotonicity testing over hypergrids. Zbl 1319.68098
2014
The one-way communication complexity of Hamming distance. Zbl 1213.68334
Jayram, T. S.; Kumar, Ravi; Sivakumar, D.
2008
Unconditional pseudorandom generators for low degree polynomials. Zbl 1213.68274
Lovett, Shachar
2009
Discrete-query quantum algorithm for NAND trees. Zbl 1213.68283
Childs, Andrew M.; Cleve, Richard; Jordan, Stephen P.; Yonge-Mallo, David
2009
Semidefinite programs for completely bounded norms. Zbl 1213.81047
Watrous, John
2009
Tensor products of weakly smooth codes are robust. Zbl 1213.68252
Ben-Sasson, Eli; Viderman, Michael
2009
Monotone expanders: constructions and applications. Zbl 1213.68440
Dvir, Zeev; Wigderson, Avi
2010
Tight bounds on the average sensitivity of k-CNF. Zbl 1213.68416
Amano, Kazuyuki
2011
Revenue submodularity. Zbl 1246.91054
Dughmi, Shaddin; Roughgarden, Tim; Sundararajan, Mukund
2012
Tensor-based hardness of the shortest vector problem to within almost polynomial factors. Zbl 1253.68152
Haviv, Ishay; Regev, Oded
2012
Anti-concentration for polynomials of independent random variables. Zbl 1392.68193
Meka, Raghu; Nguyen, Oanh; Vu, Van
2016
Tight hardness of the non-commutative Grothendieck problem. Zbl 1387.68122
Briët, Jop; Regev, Oded; Saket, Rishi
2017
Solving packing integer programs via randomized rounding with alterations. Zbl 1297.68259
Bansal, Nikhil; Korula, Nitish; Nagarajan, Viswanath; Srinivasan, Aravind
2012
Inapproximability of NP-complete variants of Nash equilibrium. Zbl 1366.68071
Austrin, Per; Braverman, Mark; Chlamtáč, Eden
2013
Making polynomials robust to noise. Zbl 1366.68063
Sherstov, Alexander A.
2013
Approximating the AND-OR tree. Zbl 1328.68078
Sherstov, Alexander A.
2013
All quantum adversary methods are equivalent. Zbl 1213.68289
Špalek, Robert; Szegedy, Mario
2006
Iterative construction of Cayley expander graphs. Zbl 1213.05127
Rozenman, Eyal; Shalev, Aner; Wigderson, Avi
2006
Quantum versus classical proofs and advice. Zbl 1213.68290
Aaronson, Scott; Kuperberg, Greg
2007
Approximation algorithms for unique games. Zbl 1213.68320
Trevisan, Luca
2008
An $$O(k^3\log n)$$-approximation algorithm for vertex-connectivity survivable network design. Zbl 1253.68167
Chuzhoy, Julia; Khanna, Sanjeev
2012
On the (non) $$\mathsf{NP}$$-hardness of computing circuit complexity. Zbl 1378.68053
Murray, Cody D.; Williams, R. Ryan
2017
Conditional random fields, planted constraint satisfaction, and entropy concentration. Zbl 1351.68190
Abbe, Emmanuel; Montanari, Andrea
2015
Non-commutative arithmetic circuits with division. Zbl 1403.94130
Hrubeš, Pavel; Wigderson, Avi
2015
The quantum and classical complexity of translationally invariant tiling and Hamiltonian problems. Zbl 1366.68073
Gottesman, Daniel; Irani, Sandy
2013
Pseudorandomness for width-2 branching programs. Zbl 1300.68037
Bogdanov, Andrej; Dvir, Zeev; Verbin, Elad; Yehudayoff, Amir
2013
A non-linear time lower bound for Boolean branching programs. Zbl 1213.68302
Ajtai, Miklós
2005
Time-space efficient simulations of quantum computations. Zbl 1253.68136
Van Melkebeek, Dieter; Watson, Thomas
2012
SDP gaps from pairwise independence. Zbl 1253.68141
Benabbas, Siavosh; Georgiou, Konstantinos; Magen, Avner; Tulsiani, Madhur
2012
Span-program-based quantum algorithm for evaluating formulas. Zbl 1279.68097
Reichardt, Ben; Špalek, Robert
2012
How to verify a quantum computation. Zbl 1395.68142
2018
A tradeoff between length and width in resolution. Zbl 1355.03047
Thapen, Neil
2016
The complexity of parity graph homomorphism: an initial investigation. Zbl 1336.68122
Faben, John; Jerrum, Mark
2015
On the hardness of learning with errors with binary secrets. Zbl 1412.68072
Micciancio, Daniele
2018
Quantum-walk speedup of backtracking algorithms. Zbl 1417.68046
Montanaro, Ashley
2018
Circumventing $$d$$-to-$$1$$ for approximation resistance of satisfiable predicates strictly containing parity of width at least four. Zbl 1366.68084
Wenner, Cenny
2013
Hardness of vertex deletion and project scheduling. Zbl 1366.68083
Svensson, Ola
2013
A regularity lemma and low-weight approximators for low-degree polynomial threshold functions. Zbl 1366.68089
Diakonikolas, Ilias; Servedio, Rocco A.; Tan, Li-Yang; Wan, Andrew
2014
Bounding the sensitivity of polynomial threshold functions. Zbl 1366.68096
2014
Width-parametrized SAT: time-space tradeoffs. Zbl 1319.68094
Allender, Eric; Chen, Shiteng; Lou, Tiancheng; Papakonstantinou, Periklis A.; Tang, Bangsheng
2014
Testing linear-invariant non-linear properties. Zbl 1246.68259
Bhattacharyya, Arnab; Chen, Victor; Sudan, Madhu; Xie, Ning
2011
Inverse conjecture for the Gowers norm is false. Zbl 1282.11009
Lovett, Shachar; Meshulam, Roy; Samorodnitsky, Alex
2011
On circuit lower bounds from derandomization. Zbl 1247.68091
Aaronson, Scott; van Melkebeek, Dieter
2011
Improved bounds for speed scaling in devices obeying the cube-root rule. Zbl 1253.68068
Bansal, Nikhil; Chan, Ho-Leung; Katz, Dmitriy; Pruhs, Kirk
2012
Tight bounds on the approximability of almost-satisfiable Horn SAT and exact hitting set. Zbl 1255.68303
Guruswami, Venkatesan; Zhou, Yuan
2012
Inapproximability of the shortest vector problem: toward a deterministic reduction. Zbl 1282.68127
Micciancio, Daniele
2012
Interactive proofs for $$\mathsf{BQP}$$ via self-tested graph states. Zbl 1362.68087
McKague, Matthew
2016
Lower bounds for non-commutative skew circuits. Zbl 1393.68063
Limaye, Nutan; Malod, Guillaume; Srinivasan, Srikanth
2016
Communication complexity of set-disjointness for all probabilities. Zbl 1365.68259
Göös, Mika; Watson, Thomas
2016
The power of nondeterminism in self-assembly. Zbl 1366.68054
Bryans, Nathaniel; Chiniforooshan, Ehsan; Doty, David; Kari, Lila; Seki, Shinnosuke
2013
The complexity of the fermionant and immanants of constant width. Zbl 1366.68078
Mertens, Stephan; Moore, Cristopher
2013
Almost $$k$$-wise vs. $$k$$-wise independent permutations, and uniformity for general group actions. Zbl 1297.68183
Alon, Noga; Lovett, Shachar
2013
Lower bounds for the average and smoothed number of Pareto-optima. Zbl 1354.90126
Brunsch, Tobias; Goyal, Navin; Rademacher, Luis; Röglin, Heiko
2014
Learning $$k$$-modal distributions via testing. Zbl 1319.68119
Daskalakis, Constantinos; Diakonikolas, Ilias; Servedio, Rocco A.
2014
On reconstruction and testing of read-once formulas. Zbl 1319.68113
Shpilka, Amir; Volkovich, Ilya
2014
Limits on the universal method for matrix multiplication. Zbl 07413496
Alman, Josh
2021
Barriers for fast matrix multiplication from irreversibility. Zbl 07413497
Christandl, Matthias; Vrana, Péter; Zuiddam, Jeroen
2021
The polynomial method strikes back: tight quantum query bounds via dual polynomials. Zbl 1462.68060
Bun, Mark; Kothari, Robin; Thaler, Justin
2020
On the hardness of approximate and exact (bichromatic) maximum inner product. Zbl 1462.68067
Chen, Lijie
2020
On the hardness of approximating the $$k$$-Way Hypergraph Cut problem. Zbl 1462.68066
Chekuri, Chandra; Li, Shi
2020
Relaxed locally correctable codes. Zbl 1477.68110
Gur, Tom; Ramnarayan, Govind; Rothblum, Ron
2020
Fourier and circulant matrices are not rigid. Zbl 1477.68117
Dvir, Zeev; Liu, Allen
2020
Algebraic dependencies and $$\mathsf{PSPACE}$$ algorithms in approximative complexity over any field. Zbl 1456.68058
Guo, Zeyu; Saxena, Nitin; Sinhababu, Amit
2019
Matrix rigidity and the Croot-Lev-Pach lemma. Zbl 1477.68116
Dvir, Zeev; Edelman, Benjamin L.
2019
Closure results for polynomial factorization. Zbl 1477.68106
Chou, Chi-Ning; Kumar, Mrinal; Solomon, Noam
2019
Subsets of Cayley graphs that induce many edges. Zbl 07166714
Gowers, Timothy; Janzer, Oliver
2019
Potential-function proofs for gradient methods. Zbl 1482.90145
Bansal, Nikhil; Gupta, Anupam
2019
Outlaw distributions and locally decodable codes. Zbl 1477.94080
Briët, Jop; Dvir, Zeev; Gopi, Sivakanth
2019
How to verify a quantum computation. Zbl 1395.68142
2018
On the hardness of learning with errors with binary secrets. Zbl 1412.68072
Micciancio, Daniele
2018
Quantum-walk speedup of backtracking algorithms. Zbl 1417.68046
Montanaro, Ashley
2018
Average-case lower bounds and satisfiability algorithms for small threshold circuits. Zbl 1395.68138
Chen, Ruiwen; Santhanam, Rahul; Srinivasan, Srikanth
2018
Randomized query complexity of sabotaged and composed functions. Zbl 1398.68186
Ben-David, Shalev; Kothari, Robin
2018
Certifying polynomials for $$\mathsf{AC}^0[\oplus]$$ circuits, with applications to lower bounds and circuit compression. Zbl 1412.68071
Kopparty, Swastik; Srinivasan, Srikanth
2018
New algorithms and lower bounds for circuits with linear threshold gates. Zbl 1410.68127
Williams, R. Ryan
2018
On the size of homogeneous and of depth-four formulas with low individual degree. Zbl 1410.68125
Kayal, Neeraj; Saha, Chandan; Tavenas, Sébastien
2018
Succinct hitting sets and barriers to proving lower bounds for algebraic circuits. Zbl 1412.68081
Forbes, Michael A.; Shpilka, Amir; Volk, Ben Lee
2018
Simplified separation of information and communication. Zbl 1412.68060
Rao, Anup; Sinha, Makrand
2018
Separation of unbounded-error models in multi-party communication complexity. Zbl 1414.68027
2018
On multiparty communication with large versus unbounded error. Zbl 1412.68061
Sherstov, Alexander A.
2018
A deterministic PTAS for the commutative rank of matrix spaces. Zbl 1395.68333
Bläser, Markus; Jindal, Gorav; Pandey, Anurag
2018
Linear-time algorithm for quantum 2SAT. Zbl 1395.68132
Arad, Itai; Santha, Miklos; Sundaram, Aarthi; Zhang, Shengyu
2018
The complexity of computing the optimal composition of differential privacy. Zbl 1395.94305
2018
Trading information complexity for error. Zbl 1394.68148
Dagan, Yuval; Filmus, Yuval; Hatami, Hamed; Li, Yaqiao
2018
Tight hardness of the non-commutative Grothendieck problem. Zbl 1387.68122
Briët, Jop; Regev, Oded; Saket, Rishi
2017
On the (non) $$\mathsf{NP}$$-hardness of computing circuit complexity. Zbl 1378.68053
Murray, Cody D.; Williams, R. Ryan
2017
Some limitations of the sum of small-bias distributions. Zbl 1387.68125
Lee, Chin Ho; Viola, Emanuele
2017
Superquadratic lower bound for 3-query locally correctable codes over the reals. Zbl 1375.94176
Dvir, Zeev; Saraf, Shubhangi; Wigderson, Avi
2017
The inapproximability of maximum single-sink unsplittable, priority and confluent flow problems. Zbl 1387.68127
Shepherd, F. Bruce; Vetta, Adrian R.
2017
Monotone projection lower bounds from extended formulation lower bounds. Zbl 1383.68036
Grochow, Joshua A.
2017
Nash equilibria in perturbation-stable games. Zbl 1380.91011
Balcan, Maria-Florina; Braverman, Mark
2017
Pseudorandomness and Fourier-growth bounds for width-3 branching programs. Zbl 1377.65003
Steinke, Thomas; Vadhan, Salil; Wan, Andrew
2017
A communication game related to the sensitivity conjecture. Zbl 1379.68151
Gilmer, Justin; Koucký, Michal; Saks, Michael
2017
Identity testing for constant-width, and any-order, read-once oblivious arithmetic branching programs. Zbl 1378.68080
Gurjar, Rohit; Korwar, Arpita; Saxena, Nitin
2017
Locally checkable proofs in distributed computing. Zbl 1401.68085
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2016
Anti-concentration for polynomials of independent random variables. Zbl 1392.68193
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2016
A tradeoff between length and width in resolution. Zbl 1355.03047
Thapen, Neil
2016
Interactive proofs for $$\mathsf{BQP}$$ via self-tested graph states. Zbl 1362.68087
McKague, Matthew
2016
Lower bounds for non-commutative skew circuits. Zbl 1393.68063
Limaye, Nutan; Malod, Guillaume; Srinivasan, Srikanth
2016
Communication complexity of set-disjointness for all probabilities. Zbl 1365.68259
Göös, Mika; Watson, Thomas
2016
Lattice sparsification and the approximate closest vector problem. Zbl 1362.68291
2016
Dual polynomials for collision and element distinctness. Zbl 1393.68055
Bun, Mark; Thaler, Justin
2016
Efficient indexing of necklaces and irreducible polynomials over finite fields. Zbl 1373.11080
Kopparty, Swastik; Kumar, Mrinal; Saks, Michael
2016
Simple proof of hardness of feedback vertex set. Zbl 1343.68095
Guruswami, Venkatesan; Lee, Euiwoong
2016
Private learning and sanitization: pure vs. approximate differential privacy. Zbl 1362.68096
Beimel, Amos; Nissim, Kobbi; Stemmer, Uri
2016
Lowest-degree $$k$$-spanner: approximation and hardness. Zbl 1393.68187
Chlamtáč, Eden; Dinitz, Michael
2016
Upper bounds on quantum query complexity inspired by the Elitzur-Vaidman bomb tester. Zbl 1353.81035
Lin, Cedric Yen-Yu; Lin, Han-Hsuan
2016
Dichotomies in equilibrium computation and membership of PLC markets in FIXP. Zbl 1415.91191
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2016
Approximation algorithms for hypergraph small-set expansion and small-set vertex expansion. Zbl 1393.68190
Louis, Anand; Makarychev, Yury
2016
Minimizing maximum flow-time on related machines. Zbl 1391.90239
Bansal, Nikhil; Cloostermans, Bouke
2016
Robust lower bounds for communication and stream computation. Zbl 1392.68191
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2016
Maximizing the spread of influence through a social network. Zbl 1337.91069
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2015
New lower bounds for the border rank of matrix multiplication. Zbl 1336.68102
Landsberg, Joseph M.; Ottaviani, Giorgio
2015
The projection games conjecture and the NP-hardness of $$\ln n$$-approximating Set-Cover. Zbl 1335.68097
Moshkovitz, Dana
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How hard is it to approximate the Jones polynomial? Zbl 1337.68109
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Computing the partition function for cliques in a graph. Zbl 1351.05212
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List-decoding multiplicity codes. Zbl 1397.94127
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Conditional random fields, planted constraint satisfaction, and entropy concentration. Zbl 1351.68190
Abbe, Emmanuel; Montanari, Andrea
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Non-commutative arithmetic circuits with division. Zbl 1403.94130
Hrubeš, Pavel; Wigderson, Avi
2015
The complexity of parity graph homomorphism: an initial investigation. Zbl 1336.68122
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Quantum interactive proofs and the complexity of separability testing. Zbl 1336.68082
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Adapt or die: polynomial lower bounds for non-adaptive dynamic data structures. Zbl 1351.68084
Brody, Joshua; Larsen, Kasper Green
2015
On some extensions of the FKN theorem. Zbl 1352.60029
Jendrej, Jacek; Oleszkiewicz, Krzysztof; Wojtaszczyk, Jakub O.
2015
Quantum algorithm for monotonicity testing on the hypercube. Zbl 1351.68105
Belovs, Aleksandrs; Blais, Eric
2015
On the NP-hardness of approximating ordering-constraint satisfaction problems. Zbl 1335.68094
Austrin, Per; Manokaran, Rajsekar; Wenner, Cenny
2015
A new regularity lemma and faster approximation algorithms for low threshold rank graphs. Zbl 1337.68295
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2015
The complexity of deciding statistical properties of samplable distributions. Zbl 1336.68108
Watson, Thomas
2015
Matchgates revisited. Zbl 1342.68156
Cai, Jin-Yi; Gorenstein, Aaron
2014
Grothendieck inequalities for semidefinite programs with rank constraint. Zbl 1297.68261
Briët, Jop; de Oliveira Filho, Fernando Mário; Vallentin, Frank
2014
The need for structure in quantum speedups. Zbl 1298.81045
Aaronson, Scott; Ambainis, Andris
2014
An optimal lower bound for monotonicity testing over hypergrids. Zbl 1319.68098
2014
A regularity lemma and low-weight approximators for low-degree polynomial threshold functions. Zbl 1366.68089
Diakonikolas, Ilias; Servedio, Rocco A.; Tan, Li-Yang; Wan, Andrew
2014
Bounding the sensitivity of polynomial threshold functions. Zbl 1366.68096
2014
Width-parametrized SAT: time-space tradeoffs. Zbl 1319.68094
Allender, Eric; Chen, Shiteng; Lou, Tiancheng; Papakonstantinou, Periklis A.; Tang, Bangsheng
2014
Lower bounds for the average and smoothed number of Pareto-optima. Zbl 1354.90126
Brunsch, Tobias; Goyal, Navin; Rademacher, Luis; Röglin, Heiko
2014
Learning $$k$$-modal distributions via testing. Zbl 1319.68119
Daskalakis, Constantinos; Diakonikolas, Ilias; Servedio, Rocco A.
2014
On reconstruction and testing of read-once formulas. Zbl 1319.68113
Shpilka, Amir; Volkovich, Ilya
2014
Approximation algorithm for non-Boolean Max-$$k$$-CSP. Zbl 1319.68254
Makarychev, Konstantin; Makarychev, Yury
2014
Efficient rounding for the noncommutative Grothendieck inequality. Zbl 1302.68323
Naor, Assaf; Regev, Oded; Vidick, Thomas
2014
Improved inapproximability for TSP. Zbl 1366.68077
Lampis, Michael
2014
Dimension-free $$L_2$$ maximal inequality for spherical means in the hypercube. Zbl 1298.42022
Harrow, Aram W.; Kolla, Alexandra; Schulman, Leonard J.
2014
Tight bounds for monotone switching networks via Fourier analysis. Zbl 1319.68100
Chan, Siu Man; Potechin, Aaron
2014
Symmetry coincides with nondeterminism for time-bounded auxiliary pushdown automata. Zbl 1366.68068
Allender, Eric; Lange, Klaus-Jörn
2014
Approximation resistance on satisfiable instances for predicates with few accepting inputs. Zbl 1319.68111
Huang, Sangxia
2014
The computational complexity of linear optics. Zbl 1298.81046
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2013
Inapproximability of NP-complete variants of Nash equilibrium. Zbl 1366.68071
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2013
Making polynomials robust to noise. Zbl 1366.68063
Sherstov, Alexander A.
2013
Approximating the AND-OR tree. Zbl 1328.68078
Sherstov, Alexander A.
2013
The quantum and classical complexity of translationally invariant tiling and Hamiltonian problems. Zbl 1366.68073
Gottesman, Daniel; Irani, Sandy
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Pseudorandomness for width-2 branching programs. Zbl 1300.68037
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Circumventing $$d$$-to-$$1$$ for approximation resistance of satisfiable predicates strictly containing parity of width at least four. Zbl 1366.68084
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Svensson, Ola
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Almost $$k$$-wise vs. $$k$$-wise independent permutations, and uniformity for general group actions. Zbl 1297.68183
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### Cited by 2,650 Authors
13 Guruswami, Venkatesan 12 Hoefer, Martin 12 Wu, Weili 10 Bonnet, Edouard 10 Palazuelos, Carlos 9 Gargano, Luisa 9 Lampis, Michael 9 Sherstov, Alexander A. 8 Ambainis, Andris 8 Goldberg, Leslie Ann 8 Grigorescu, Elena 8 Marx, Dániel 8 Miyano, Eiji 8 Pitassi, Toniann 8 Rautenbach, Dieter 8 Srinivasan, Srikanth 8 Thaler, Justin 8 Viola, Emanuele 7 Aaronson, Scott 7 Allender, Eric W. 7 Bazgan, Cristina 7 Bun, Mark 7 Chekuri, Chandra S. 7 Childs, Andrew M. 7 Cordasco, Gennaro 7 Huang, Chien-Chung 7 Le Gall, François 7 Mahajan, Meena 7 Naor, Assaf 7 Paschos, Vangelis Th. 7 Pokutta, Sebastian 7 Rescigno, Adele Anna 7 Tuza, Zsolt 7 Wiese, Andreas 7 Wigderson, Avi 6 Barvinok, Alexander I. 6 Belovs, Aleksandrs 6 Briët, Jop 6 Cai, Jin-Yi 6 Chalermsook, Parinya 6 D’Angelo, Gianlorenzo 6 Elbassioni, Khaled M. 6 Khot, Subhash Ajit 6 Landsberg, Joseph Montague 6 Limaye, Nutan 6 Makino, Kazuhisa 6 Massarenti, Alex 6 Roughgarden, Tim 6 Servedio, Rocco A. 6 Shpilka, Amir 6 Sikora, Florian 6 Tzameret, Iddo 6 Vaccaro, Ugo 6 van Melkebeek, Dieter 6 Yoshida, Yuichi 5 Alon, Noga M. 5 Asahiro, Yuichi 5 Ben-Sasson, Eli 5 Borodin, Allan B. 5 Braverman, Mark 5 Christandl, Matthias 5 Chuzhoy, Julia 5 Dantchev, Stefan Stoyanov 5 Deligkas, Argyrios 5 Fearnley, John 5 Filmus, Yuval 5 Fiorini, Samuel 5 Fu, Bin 5 Fu, Zhiguo 5 Gur, Tom 5 Halldórsson, Magnús Mar 5 Harrow, Aram Wettroth 5 Im, Sungjin 5 Impagliazzo, Russell 5 Jansson, Jesper 5 Manurangsi, Pasin 5 Martin, Barnaby D. 5 Nishimura, Harumichi 5 Ordyniak, Sebastian 5 Porat, Ely 5 Qiao, Youming 5 Raz, Ran 5 Regev, Oded 5 Regts, Guus 5 Reichman, Daniel 5 Santha, Miklos 5 Shapira, Asaf 5 Spirakis, Paul G. 5 Suchý, Ondřej 5 Thai, My T. 5 Viderman, Michael 5 Vidick, Thomas 5 Wong, Thomas G. 4 Abbe, Emmanuel 4 Anshelevich, Elliot 4 Bansal, Nikhil 4 Bausch, Johannes 4 Brandão, Fernando G. S. L. 4 Brody, Joshua E. 4 Caragiannis, Ioannis ...and 2,550 more Authors
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### Cited in 256 Journals
95 Theoretical Computer Science 93 SIAM Journal on Computing 91 Algorithmica 63 Computational Complexity 40 Discrete Applied Mathematics 34 Theory of Computing Systems 30 Journal of Combinatorial Optimization 27 SIAM Journal on Discrete Mathematics 26 Journal of Computer and System Sciences 25 Information Processing Letters 22 Quantum Information Processing 20 Mathematical Programming. Series A. Series B 20 Discrete Optimization 17 Communications in Mathematical Physics 16 Information and Computation 14 Journal of Mathematical Physics 11 Combinatorica 11 Journal of the ACM 10 Information Sciences 10 Distributed Computing 10 Journal of Machine Learning Research (JMLR) 9 Discrete & Computational Geometry 9 Random Structures & Algorithms 9 Data Mining and Knowledge Discovery 8 Israel Journal of Mathematics 8 New Journal of Physics 7 Artificial Intelligence 7 Discrete Mathematics 7 Journal of Statistical Physics 7 Mathematics of Operations Research 7 Annals of Operations Research 7 The Electronic Journal of Combinatorics 7 Internet Mathematics 7 Theory of Computing 7 Discrete Analysis 6 Operations Research 6 Operations Research Letters 6 Computational Optimization and Applications 5 European Journal of Combinatorics 5 Journal of Cryptology 5 Journal of Global Optimization 5 Games and Economic Behavior 5 Linear Algebra and its Applications 5 SIAM Journal on Optimization 5 Annales Henri Poincaré 5 Discrete Mathematics, Algorithms and Applications 4 International Journal of Theoretical Physics 4 Physica A 4 Physics Letters. A 4 Automatica 4 Machine Learning 4 Geometric and Functional Analysis. GAFA 4 European Journal of Operational Research 4 Bulletin of the American Mathematical Society. New Series 4 The Journal of Artificial Intelligence Research (JAIR) 4 Chicago Journal of Theoretical Computer Science 4 International Journal of Quantum Information 4 Algorithms 3 Applied Mathematics and Computation 3 Computing 3 Journal of Combinatorial Theory. Series B 3 Journal of Pure and Applied Algebra 3 Networks 3 Proceedings of the American Mathematical Society 3 SIAM Journal on Control and Optimization 3 Annals of Pure and Applied Logic 3 Graphs and Combinatorics 3 Journal of Symbolic Computation 3 Probability Theory and Related Fields 3 Computers & Operations Research 3 SIAM Review 3 Cybernetics and Systems Analysis 3 Combinatorics, Probability and Computing 3 Annals of Mathematics and Artificial Intelligence 3 Foundations of Computational Mathematics 3 Journal of Discrete Algorithms 3 Foundations of Physics 3 Journal of Physics A: Mathematical and Theoretical 3 ACM Transactions on Algorithms 3 Games 3 Diskretnyĭ Analiz i Issledovanie Operatsiĭ 3 Journal of the Operations Research Society of China 3 Computer Science Review 3 ACM Transactions on Computation Theory 3 SIAM Journal on Applied Algebra and Geometry 2 Computer Physics Communications 2 Journal of Computational Physics 2 Linear and Multilinear Algebra 2 Physics Reports 2 Advances in Mathematics 2 The Annals of Probability 2 Journal of Algebra 2 Journal of Computational and Applied Mathematics 2 Journal of Functional Analysis 2 Mathematische Annalen 2 Journal of Computer Science and Technology 2 SIAM Journal on Matrix Analysis and Applications 2 Neural Computation 2 International Journal of Algebra and Computation 2 MSCS. Mathematical Structures in Computer Science ...and 156 more Journals
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### Cited in 49 Fields
940 Computer science (68-XX) 355 Combinatorics (05-XX) 291 Operations research, mathematical programming (90-XX) 218 Game theory, economics, finance, and other social and behavioral sciences (91-XX) 191 Quantum theory (81-XX) 133 Information and communication theory, circuits (94-XX) 62 Probability theory and stochastic processes (60-XX) 52 Linear and multilinear algebra; matrix theory (15-XX) 46 Mathematical logic and foundations (03-XX) 38 Numerical analysis (65-XX) 37 Statistics (62-XX) 32 Number theory (11-XX) 29 Statistical mechanics, structure of matter (82-XX) 28 Functional analysis (46-XX) 23 Biology and other natural sciences (92-XX) 21 Group theory and generalizations (20-XX) 19 Algebraic geometry (14-XX) 19 Convex and discrete geometry (52-XX) 18 Order, lattices, ordered algebraic structures (06-XX) 13 Operator theory (47-XX) 10 Commutative algebra (13-XX) 9 Harmonic analysis on Euclidean spaces (42-XX) 9 Manifolds and cell complexes (57-XX) 8 Field theory and polynomials (12-XX) 7 Calculus of variations and optimal control; optimization (49-XX) 5 Approximations and expansions (41-XX) 4 History and biography (01-XX) 4 Dynamical systems and ergodic theory (37-XX) 4 Geometry (51-XX) 4 Systems theory; control (93-XX) 3 General algebraic systems (08-XX) 3 Associative rings and algebras (16-XX) 3 Category theory; homological algebra (18-XX) 3 Topological groups, Lie groups (22-XX) 3 Real functions (26-XX) 3 Measure and integration (28-XX) 3 Ordinary differential equations (34-XX) 3 Partial differential equations (35-XX) 2 General and overarching topics; collections (00-XX) 2 Nonassociative rings and algebras (17-XX) 2 Functions of a complex variable (30-XX) 2 Several complex variables and analytic spaces (32-XX) 2 Differential geometry (53-XX) 2 Fluid mechanics (76-XX) 1 Special functions (33-XX) 1 Abstract harmonic analysis (43-XX) 1 General topology (54-XX) 1 Mechanics of deformable solids (74-XX) 1 Relativity and gravitational theory (83-XX) | 2022-05-24 05:37:12 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6415566802024841, "perplexity": 13794.626148147756}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-21/segments/1652662564830.55/warc/CC-MAIN-20220524045003-20220524075003-00379.warc.gz"} |
https://www.or-exchange.org/questions/10550/convert-nlp-constraint-into-a-linear-one | # Convert NLP constraint into a linear one
0 Hy, I have a problem with a non linear constraint. In an Optimization problem i have this constraint X*Y >= K with X,Y continuous variables and bounded (X€[Xm,XM] Y€[Ym,YM]) and K constant. There is some way to convert this non linear constraint into a linear one (i mean a set of linear). Thanks asked 27 Oct '14, 11:49 Giovanni 11●1 accept rate: 0%
One Answer:
2 With $$Z_1 = \frac{1}{2}(X + Y)$$ and $$Z_2 = \frac{1}{2}(X - Y)$$ $$\Rightarrow$$ $$X * Y = Z_1^2 - Z_2^2$$, and – hence – $$X * Y \ge K \Leftrightarrow Z_1^2 - Z_2^2 \ge K$$ ...which allows for piecewise linear approximation [using λ-formulation, SOS2 variables, and/or other fancy stuff your modeling language + solver support]. answered 27 Oct '14, 14:33 fbahr ♦ 4.6k●7●16 accept rate: 13%
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Asked: 27 Oct '14, 11:49
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### Related questions
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http://mathematica.stackexchange.com/questions/41133/how-to-normalise-a-line-in-mathematica/41134 | # How to normalise a line in mathematica
I'm working on creating a line plot from a histogram, as in the following:
{g, {binCounts}} =
Reap[Histogram[RandomVariate[NormalDistribution[0, 1], 100],
{-2,2,0.25},
Function[{bins, counts}, Sow[counts]]]];
{g, ListLinePlot[binCounts]}
What I'd like to know is, how can I normalised this line so the area under the curve is 1? (So I can compare the shapes of these histograms independent of the number of counts)
- | 2016-07-23 21:17:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 1, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7174005508422852, "perplexity": 1410.8497260501038}, "config": {"markdown_headings": true, "markdown_code": false, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-30/segments/1469257823670.44/warc/CC-MAIN-20160723071023-00202-ip-10-185-27-174.ec2.internal.warc.gz"} |
https://proofwiki.org/wiki/User:Jshflynn/archive/preMarch2013 | # User:Jshflynn/archive/preMarch2013
## Strong Examples of Concepts
We frequently show that two concepts are equal.
How about showing that two concepts are not equal is that important?
If we were to have an example namespace from the beginning then I would say that:
As soon as the concept of Abelian Group is defined it must be proved that there are groups that are not Abelian otherwise we are unjustified in introducing the concept. In particular we would have to add an example to the examples of groups that we would call a strong example relative to Abelian Group
I need other opinions on this.
I refer you to the P = NP problem for an example where it is very relevant to introduce a new class of concepts (as a sub- or superclass of something bigger), even though we don't know whether or not it is a proper sub- or superclass. Other factors of importance are e.g. conceptual clarity or convenience. OTOH if two classes are not equal then it would be apt to have examples in every appropriate part of the resulting Venn diagram. — Lord_Farin (talk) 18:19, 25 February 2013 (UTC)
## What is this in disguise?
A concept $C$ is example admitting if there are examples of it. Write $C \mathsf{ex:} e$ to denote that $e$ is an example of $C$ and $C \overline{\mathsf{ex:}} e$ to denote that $e$ is not an example of $C$.
If we consider "example admitting" as a concept in its own right and denote it by $E$ then we see that it applies to itself. That is, there exists a concept $C$ that is example admitting and so $C$ is an example of $E$ meaning that $E$ is an example of $E$.
## Algebraic Structure and Metric Charts
I can't seem to find where but someone proposed a table for all the names of the algebraic structures (or should I say varieties :) ) given which axioms they have.
We could do the same for metrics (and possibly other structures) seeing as how I read today that nearly every possible weakening of those axioms has been studied.
Also speaking of tables you could possibly have a table showing which axioms are independent. Hmm... needs more thought.
I've been seeing these "compound pages" a lot lately with basic properties of a function listed or all the little variations that a word may have and I like them a lot indeed.
--Jshflynn (talk) 16:58, 8 February 2013 (UTC)
Cf. Definition talk:Semiring (Abstract Algebra). Idea needs development. Likely, fields need further development (in terms of both results and sources) to make the exercise worthwhile and less prone to errors. --Lord_Farin (talk) 18:10, 8 February 2013 (UTC)
## Checkerboard Matrices
Square matrices partitioned as a checkerboard would be.
Let blacks be zero matrices.
Is this closed under matrix multiplication?
What is the set of left identities?
--Jshflynn (talk) 11:07, 6 February 2013 (UTC)
It looks like the set of square matrices is closed under matrix multiplication. So it's both a vector subspace and a ring. Assuming the standard convention that there is a white square at the lower right corner. --Anghel (talk) 23:11, 6 February 2013 (UTC)
Correct sir! :) --Jshflynn (talk) 16:58, 8 February 2013 (UTC)
## What to do?
I am trying to understand just the essence of Double Orthocomplement is Closed Linear Span.
Okay, so I look at $\mathbb R^2$ which is a Hilbert space.
I look at the singleton $\{(1, 0)\}$.
I see the orthocomplement is the whole of the $y$ axis.
I see the orthocomplement of the $y$ axis unioned with $\{(1, 0)\}$ is the $x$ and the $y$ axis. (right?)
Now, what's the span of $\{(1, 0)\}$? Well that's just the $x$ axis isn't it?
What's the closure of the $x$ axis if I think of the usual topology on $\mathbb R^2$?
Surely it's not the $x$ axis unioned with the $y$ axis?
Can anyone help me understand how?
$\{(1,0)\}$ is not in its own orthocomplement. --Lord_Farin (talk) 07:56, 31 January 2013 (UTC)
I get it now $(\{1,0\}^\perp)^\perp$ is the whole of the $x$ axis only which is the closed linear span of $\{(1,0)\}$. It seems I needed sleep :) Thanks LF. --Jshflynn (talk) 11:38, 31 January 2013 (UTC)
In time I'll learn to enjoy posting proofs.
For now I find it most relaxing adding sources and references :)
Onwards ProofWiki!
## Quicker Typing Help
If you find yourself typing "Definition:" or some other key sequence repeatedly I have found the program AutoHotKeys to be very good:
AutoHotKeys website
There is also the link in "ProofWiki Specific" right below your edit pane. Saves learning random nonsense. --prime mover (talk) 07:15, 14 December 2012 (UTC)
The act of moving one's hand to the mouse, then the pointer to the link below, then click, then move hand back to keyboard is generally more expensive than simply typing the string yourself. Moreover, it presupposes that one does not use an external editor for PW (which I have started to do just a few days ago, the highlighting and improved search/replace functionality make it worthwhile). Thank you Jshflynn, I'll consider it later, when I get home. --Lord_Farin (talk) 12:04, 14 December 2012 (UTC)
Each to his/her own - but I have less patience with learning new stuff nowadays. Keeping up with tech is becoming a headache and more than. The links below the edit pane are just what I need. --prime mover (talk) 20:13, 14 December 2012 (UTC)
## Thought
In graph theory I think that connectedness of vertices is an equivalence relation and the elements of the quotient set are the components of the graph. If that's true I don't know if it's worth proving. --Jshflynn (talk) 21:04, 21 December 2012 (UTC)
It seems to be correct (assuming that connectedness means "exists path" and the graph is undirected). Worth adding, I think. --Lord_Farin (talk) 21:58, 21 December 2012 (UTC)
Only in an undirected graph. Funny but I thought I'd already proved this. If not, then go for it because (though trivial) it's important. --prime mover (talk) 22:15, 21 December 2012 (UTC)
Aha - seems I have done. Graph Connectedness is Equivalence Relation. --prime mover (talk) 22:17, 21 December 2012 (UTC)
Excellent. Had I simply Ctrl F'd 'Equivalence' on the proof index page I would have found it and the corollary that alphabetically precedes it. If you would like a break from the topology section (which is coming along fantastically btw) here's another easy one: "The deletion of a cyclic edge in a complete graph is a complete graph" (the book I am reading at the moment though calls cycle's circuits and what you might think would be called a 'circuitous edge' is just a 'circuit edge', it is from 1981 however so there could have been a terminological shift since then). --Jshflynn (talk) 23:23, 21 December 2012 (UTC)
## Deposit
I will have to deposit this here for the future:
$\displaystyle\left\vert{ \prod_{j \in J} \left\vert{ \prod_{i \in J} \left\vert{ \left({\mathcal{P}\left({S / \mathcal{R}_f}\right)_j}\right)_i }\right\vert }\right\vert}\right\vert$
## Emerging Trends
I am keeping a note here of emerging phenomena on ProofWiki for me to think about. I am aware it is not organised.
• Theorems that are special cases of other theorems.
• Definitions that are special cases of other definitions.
• Processes to generate new theorems (duality principles, the machinery of category theory (corollary spaces?)).
Other undeveloped thoughts:
• Some theorems are not used in the proof of anything else. Perhaps have community consequence challenges? The players have to prove something else using the theorem at least once.
Just noticed this. I don't see this as being a problem. Certain theorems are "end points" in that they exist as an end in themselves. FLT is an example I can think of (although you'll tell me it has a use now).
• Lemma (or Exercise) namespace? The idea being that people store answers to questions in books so that more people can have a go of using LaTeX and wikis (the book in question of course not having the answers). Reward users by saying that their work has been "promoted" to the theorem namespace and let them know that they too can do mathematics. This way the theorem namespace isn't cluttered and it's getting others involved.
Lemmas should carry on existing in the Theorems namespace, because it's not a hard-and-fast rule as to what is a lemma and what is a theorem. Lemmas are identified (usually) by having "Lemma" at the top instead of "Theorem".
Examples I'm less sure about. What I am sure of is that I would rather they did not clutter up a definition page (or proof page, come to that) but should have standalone pages. What we could do is have example categories as subcategories of either theorem or definition categories (but I understand that the namespace paradigm may be compromised by the latter - does that matter?) There could be a specific template that would go into an "example" category like we have in the existing categories and subcategories. But I haven't gone down that route because the concept of examples in general (except for the instances of topologies and groups etc.) does not interest me much. --prime mover (talk) 19:46, 18 January 2013 (UTC)
I am trying to categorise the 'complaints' into broad categories and see if there is a sweeping solution for each of them. You may improve the list if you wish:
• People that want the site to be completely different (as in like an encyclopedia or a wikiversity offshoot): If new direct them to the relevant help page. If persistent tell them to make their own. If demanding tell them to piss off.
• People that want the site to have extra stuff: I have been studying databases and the concept of views has helped me think about this. Perhaps someday in the distant future PW will have views that take full advantage of the idea of transclusion. A 'concept page' for example could have a definition at the top, then 3 or 4 examples, 3 or 4 'featured theorems' etc. People who disliked the idea could simply turn their view of them off. But this is very difficult and not worth looking into at the moment I think.
• People that want the site to look different: Disturbing that people seem to be genuinely offended by different notation. They will have to get used to it. Some people are bothered by excess notation which is understandable. PW is moving in the direction now where it suppresses notation if it has no use in the proof. So I think their complaints are as a whole attended to.
## Antitransitive Implies Antireflexive
Let:
$xy,yz \vert \overline{xz}$
Suppose:
$aa$
Then:
$aa,aa \vert \overline{aa}$
Hence:
$(xy,yz \vert \overline{xz}) \vert (\vert \overline{xx})$
$\blacksquare$
## Deposit 2
$\begin{xy} <0em,0em>*+{M_n(\mathbb{R})} = "S1", <5em,0em>*+{M_n(\mathbb{R})} = "S2", <5em,-5em>*+{\mathbb{R}} = "S3", "S1";"S2" **@{-} ?>*@{>} ?*!/_1em/{t}, "S2";"S3" **@{-} ?>*@{>} ?*!/_1em/{\operatorname{det}}, "S1";"S3" **@{-} ?>*@{>} ?<>(.4)*!/^1em/{\operatorname{det}}, \end{xy}$
I would advise you to use xymatrix instead. It allows to focus more on semantics rather than syntax. --Lord_Farin (talk) 08:15, 16 January 2013 (UTC)
Good advice. You may want to change the Definition:Commutative Diagram page if this is the case as this is where I got it from. :) --Jshflynn (talk) 09:46, 16 January 2013 (UTC)
Thanks for the pointer. Done. --Lord_Farin (talk) 19:03, 16 January 2013 (UTC)
## Deposit 3
Captain's log: I have managed to open the database. There is a lot of excess data in there.
Managed to create a program which can output:
Set: Object, Element, Comprehension Principle, ...
I am leaving it to run in the background. It will take about 6 hours.
Ugh. Came back to PC and there was an error with the 2000th file. Getting there though...
From there I will see if I can make the GML script.
## Progress
So I have the necessary data to make the graph.
For phase 1 I will just be making a simple graph that shows the connections between the definitions.
For phase 2 I'm going to colour the nodes according to their category. There are two problems though:
1. Deciding on the colouring scheme.
2. One very notable contributor on here is colour blind so I will have to find some way around that.
Stay tuned.
## Progress 2
So here is what I'm working with:
It is incomplete because proofwiki is not yet perfectly monolithic (in the words of PM) and I want to get the project moving. I believe it is sufficient to give a simple overview :)
First impression: very smart.
Can you find places in it where it is inaccurate / incomplete because of ProofWiki's lack of being completely monolithic? That is, can it be used to provide direct feedback on PW's tightness and internal cohesiveness? --prime mover (talk) 19:38, 18 January 2013 (UTC)
Very cute, indeed.
One apparent problem: the dictionary doesn't look at subpages. For instance, the entry for the word coprime is empty. This is because the page Definition:Coprime has been refactored to a degree that it doesn't link to anything but subpages, which isn't registered in the dictionary.--Anghel (talk) 19:47, 18 January 2013 (UTC)
Essentially my Macro is hunting for sections on definition pages that are headed by either "== Definition ==" or "== Formal Definition ==". It then pulls out what it sees as valid links from inside those sections.
There are some sections that are headed by "== General Definition ==" instead which is perfectly valid, I just had never seen them before.
I think I should take back what I said as looking further into it the whole problem seems to be with my program handling redirects and subpages. I think I will leave this for phase 2 though as I'm rather impatient to see if the "convert list to graph" stage of the project is actually doable. --Jshflynn (talk) 19:54, 18 January 2013 (UTC)
Neat stuff. Might be good to look into the fact that some listings end with a comma while others don't. --Lord_Farin (talk) 22:08, 18 January 2013 (UTC)
Another one: rendering of non-UTF8 chars like letters with accent and Scandinavian, Polish letters. --Lord_Farin (talk) 22:10, 18 January 2013 (UTC)
How coincidental that I was attending to the comma issue just now before I read this. You have the instincts of a programmer it seems. Thanks for the heads up on those accents, I don't think anybody would be to pleased seeing "G?nter" or something of that sort where their name should be :) --Jshflynn (talk) 22:17, 18 January 2013 (UTC)
## Report
Script checks out.
Computer's compiling it.
Progress: 1%
It's going to be slow because it's an applying algorithm to optimise the layout.
Stay tuned.
--Jshflynn (talk) 19:46, 19 January 2013 (UTC)
## On how it turned out
If A points to B then A is defined in terms of B.
The graph was produced using XGMML (approximately 75000 lines generated by a macro). There are some problems and explanations due of how they may be handled in the future:
• All node labels are in lower case English with no spaces or UTF-8 characters: This was because the program I made relied on using the node labels as IDs. Unfortunately it was my mistake that it simplified the strings when deciding what the node label would actually be. This is a simple error and can be fixed. It would take another 6 hours of compilation however and I wanted to finish in some respect tonight.
• It's difficult to read the nodes: This may be fixed if I can find a way to adjust the width of the nodes and not their height. It is another relatively simple problem I believe.
• It's difficult to see the directed edges: This may not be fixable. With words like 'iff' for example it is probably completely impossible.
• There are edge missing and nodes with the label "object": For no obvious reason 6 edges had to be removed because cytoscape didn't like it. The nodes with object on them do in fact represent words but there is no obvious reason in the code as to why this is.
• There are words floating at the bottom and tiny components at the top: This is because the data I was working with was inadequate from the beginning. I will have to return to that phase and find a way to handle redirect structures.
• There is no pinch and zoom feature: I cannot upload SVG on this wiki. This is the closest I could get.
If you dislike it in its entirety I would politely ask that you withhold your tongue as in spite of how poorly it turned out it did require a lot of work to make.
I'd like to thank Joe for directing me to the DB dump along with the rest of you for your encouragement along the way.
And now I shall get some rest :)
--Jshflynn (talk) 02:02, 20 January 2013 (UTC)
Interesting! --prime mover (talk) 06:17, 20 January 2013 (UTC) | 2020-08-03 23:00:29 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7191102504730225, "perplexity": 1165.548222217154}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-34/segments/1596439735836.89/warc/CC-MAIN-20200803224907-20200804014907-00459.warc.gz"} |
https://www.ylkz.life/deeplearning/p10553832/ | 2 动机
2.1 面临问题
This inherently sequential nature precludes parallelization within training examples, which becomes critical at longer sequence lengths, as memory constraints limit batching across examples.
Recent work has achieved significant improvements in computational efficiency through factorization tricks [21] and conditional computation, while also improving model performance in case of the latter. The fundamental constraint of sequential computation, however, remains.
2.2 解决思路
To the best of our knowledge, however, the Transformer is the first transduction model relying entirely on self-attention to compute representations of its input and output without using sequence- aligned RNNs or convolution.
3 技术手段
3.1 self-Attention
An attention function can be described as mapping a query and a set of key-value pairs to an output, where the query, keys, values, and output are all vectors. The output is computed as a weighted sum of the values, where the weight assigned to each value is computed by a compatibility function of the query with the corresponding key.
We suspect that for large values of dk, the dot products grow large in magnitude, pushing the softmax function into regions where it has extremely small gradients.
It expands the model’s ability to focus on different positions. Yes, in the example above, z1 contains a little bit of every other encoding, but it could be dominated by the the actual word itself.
Multi-head attention allows the model to jointly attend to information from different representation subspaces at different positions.
引用
[1] Vaswani A, Shazeer N, Parmar N, et al. Attention is all you need
[2] The Illustrated Transformer http://jalammar.github.io/illustrated-transformer/
[3] LANGUAGE TRANSLATION WITH TRANSFORMER https://pytorch.org/tutorials/beginner/translation_transformer.html
[4] The Annotated Transformer http://nlp.seas.harvard.edu/2018/04/03/attention.html
[5] SEQUENCE-TO-SEQUENCE MODELING WITH NN.TRANSFORMER AND TORCHTEXT https://pytorch.org/tutorials/beginner/transformer_tutorial.html | 2022-12-01 20:13:16 | {"extraction_info": {"found_math": true, "script_math_tex": 22, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6531289219856262, "perplexity": 2255.0185335872648}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-49/segments/1669446710869.86/warc/CC-MAIN-20221201185801-20221201215801-00451.warc.gz"} |
https://deepai.org/publication/transience-in-countable-mdps | DeepAI
# Transience in Countable MDPs
The Transience objective is not to visit any state infinitely often. While this is not possible in finite Markov Decision Process (MDP), it can be satisfied in countably infinite ones, e.g., if the transition graph is acyclic. We prove the following fundamental properties of Transience in countably infinite MDPs. 1. There exist uniformly ϵ-optimal MD strategies (memoryless deterministic) for Transience, even in infinitely branching MDPs. 2. Optimal strategies for Transience need not exist, even if the MDP is finitely branching. However, if an optimal strategy exists then there is also an optimal MD strategy. 3. If an MDP is universally transient (i.e., almost surely transient under all strategies) then many other objectives have a lower strategy complexity than in general MDPs. E.g., ϵ-optimal strategies for Safety and co-Büchi and optimal strategies for {0,1,2}-Parity (where they exist) can be chosen MD, even if the MDP is infinitely branching.
• 16 publications
• 8 publications
• 12 publications
• 9 publications
07/07/2020
### Strategy Complexity of Parity Objectives in Countable MDPs
We study countably infinite MDPs with parity objectives. Unlike in finit...
04/24/2018
### Learning-Based Mean-Payoff Optimization in an Unknown MDP under Omega-Regular Constraints
We formalize the problem of maximizing the mean-payoff value with high p...
04/25/2018
### Distribution-based objectives for Markov Decision Processes
We consider distribution-based objectives for Markov Decision Processes ...
09/12/2022
### Statistical Estimation of Confounded Linear MDPs: An Instrumental Variable Approach
In an Markov decision process (MDP), unobservable confounders may exist ...
04/25/2022
### Strategy Synthesis for Global Window PCTL
Given a Markov decision process (MDP) M and a formula Φ, the strategy sy...
07/10/2020
### Efficient MDP Analysis for Selfish-Mining in Blockchains
A proof of work (PoW) blockchain protocol distributes rewards to its par...
01/16/2020
### Optimal by Design: Model-Driven Synthesis of Adaptation Strategies for Autonomous Systems
Many software systems have become too large and complex to be managed ef... | 2023-02-09 09:02:26 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8482171893119812, "perplexity": 3705.9780158344606}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764501555.34/warc/CC-MAIN-20230209081052-20230209111052-00813.warc.gz"} |
https://community.khronos.org/t/confusion-about-uniform-buffer-binding-binary-format/108969 | # Confusion about uniform buffer binding binary format
I have experienced a great deal confusion about the alignment of uniform structs in GLSL bound to a Vulkan pipeline. For context, note that throughout I am using Vulkan 1.3 and the latest version of glslangValidator to compile GLSL to SPIR-V (using the -V flag).
I had assumed (it now appears mistakenly) that all structs bound this way would adhere to the binary layout described by the Vulkan spec here (). The spec explicitly states that the Uniform storage class (which I assumed corresponded to the uniform struct in GLSL but later started to question) uses the “scalar” alignment rules (this effectively means “packed” in most cases) for GPU’s with the scalarBlockLayout attribute (which mine has). This conforms with my intuition and expectations as it usually matches the layout of C and C++ structs and does not require any padding to be inserted into array buffers which should match the native array layout of nearly all languages.
I quickly observed that this was not the layout actually being used, but only corresponded to it in some special cases (e.g. 4\times 4 matrices). By trial and error I determined that, for example, 2\times2 matrices require padding of the columns.
On later investigation I found that this page () in the OpenGL wiki states that uniform cannot use the std430 layout which the Vulkan spec claims to be describing. For the hell of it I tried explicitly annotating my block as std430 and it indeed gives an error message informing me that I’m not allowed to do that for uniform. I started adding the std140 annotation which should guarantee that it matches the layout described in the OpenGL spec (). So far this seems to work.
So, in summary, I think I have found that when compiling for Vulkan uniform block types use a format described in the OpenGL spec, while I still assume buffer and other struct types use a format that matches what I am seeing in the Vulkan spec.
I would like to verify from anyone who would be kind enough to confirm that I am understanding this correctly, but I also feel like I’m still missing something because of the Vulkan specs explicit mention of Uniform blocks. My current theory is that Vulkan is that the Vulkan spec is describing SPIR-V but that the relationship between GLSL abstractions and the underlying SPIR-V output is far less obvious than I had assumed. Any additional context to clarify the situation would be appreciated. Thanks.
(Vulkan 1.2+) If so, you can use std430 layout on UBOs.
The base Vulkan GLSL customization indicates that the default layouts are std140 for UBOs and std430 for SSBOs and Push Constants:
You also may need to add the GL_EXT_scalar_block_layout GLSL extension into your shader in order for it to compile. | 2023-03-31 05:45:04 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5138193964958191, "perplexity": 2151.614493747962}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296949573.84/warc/CC-MAIN-20230331051439-20230331081439-00467.warc.gz"} |
http://www.amp.i.kyoto-u.ac.jp/tecrep/abst/2007/2007-006.html | Department of Applied Mathematics & Physics, Kyoto University
### Technical Report 2007-006 (February 06, 2007) A Simple Extreme Subsets Algorithm for Submodular and Posi-modular Set Functions by Hiroshi Nagamochi
Let $f$ be a set function on a finite set $V$. A pair $\{u,v\}\subseteq V$ is called {\em flat} in $f$ if $f(X)\geq \min_{x\in X}f(\{x\})$ holds for all subsets $X\subseteq V$ with $|X\cap \{u,v\}|=1$. A subset $X\subseteq V$ is called an extreme subset of $f$ if $f(Y)>f(X)$ holds for all nonempty and proper subsets $Y$ of $X$. In this paper, we first define a minimum degree ordering (MD ordering) of $V$, and show that the last two elements in an MD ordering give a flat pair of $f$ if $f$ is symmetric and crossing submodular. Based on this, we then give a simple $O(|V|^3)$-oracle time algorithm for computing all extreme subsets of a set function $g$ if $g$ is symmetric and crossing submodular or intersecting submodular and posi-modular. | 2018-01-22 23:44:15 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8585535883903503, "perplexity": 264.7336610315812}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-05/segments/1516084891546.92/warc/CC-MAIN-20180122232843-20180123012843-00040.warc.gz"} |
http://www.jstor.org/stable/23691091 | ## Access
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Journal Article
# The Location of the Transporting System for Inorganic Carbon and the Nature of the Form Translocated in Chlamydomonas reinhardtii
Y. MARCUS, M. VOLOKITA and A. KAPLAN
Journal of Experimental Botany
Vol. 35, No. 157 (August 1984), pp. 1136-1144
Stable URL: http://www.jstor.org/stable/23691091
Page Count: 9
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## Abstract
The permeability of the plasmalemma of Chlamydomonas reinhardtii cells was increased by treatment with poly-L-lysine or dimethylsulphoxide as indicated by 3-phosphoglyceric acid dependent O2 evolution. These treatments decreased the ability of the cells to accumulate inorganic carbon internally and hence their photosynthetic affinity for inorganic carbon in the medium. With saturating light and inorganic carbon, the photosynthetic rate was less affected by the poly-L-lysine and dimethylsulphoxide treatments. Thus the poly-L-lysine and dimethylsulphoxide did not alter the activity of the chloroplasts but rather made the intracellular inorganic carbon pool more freely exchangeable with the medium. It is concluded that the transporting system for inorganic carbon is located at the plasmalemma. Treatment with Diamox, an inhibitor of carbonic anhydrase, did not affect photosynthetic rate and accumulation of inorganic carbon when CO2 was supplied but strongly inhibited both parameters when $\mathrm{H}\mathrm{C}{\mathrm{O}}_{3}^{-}$ was supplied. In a mutant of Chlamydomonas reinhardtii lacking a cell wall, carbonic anhydrase leaks to the medium and uptake of inorganic carbon is much faster when CO2 is supplied than when $\mathrm{H}\mathrm{C}{\mathrm{O}}_{3}^{-}$ is supplied. These results suggest that CO2 rather than $\mathrm{H}\mathrm{C}{\mathrm{O}}_{3}^{-}$ is the inorganic carbon species that is actively translocated across the plasmalemma.
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• 1144 | 2017-03-27 00:35:39 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.307467520236969, "perplexity": 9544.637691670228}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-13/segments/1490218189313.82/warc/CC-MAIN-20170322212949-00581-ip-10-233-31-227.ec2.internal.warc.gz"} |
https://plainmath.net/calculus-1/33574-simplify-the-indicated-limits-on-the-following-lim-x-to-infty-frac-3x | defazajx
2021-10-31
SImplify the indicated limits on the following.
$\underset{x\to \mathrm{\infty }}{lim}\frac{3{x}^{2}+5}{{x}^{2}+1}$
grbavit
According to the given information, it is required to find the limit.
$\underset{x\to \mathrm{\infty }}{lim}\frac{3{x}^{2}+5}{{x}^{2}+1}$
Now find the value of limit.
$\underset{x\to \mathrm{\infty }}{lim}\frac{3{x}^{2}+5}{{x}^{2}+1}=\underset{x\to \mathrm{\infty }}{lim}\frac{{x}^{2}\left(3+\frac{5}{{x}^{2}}\right)}{{x}^{2}\left(1+\frac{1}{{x}^{2}}\right)}$
$=\underset{x\to \mathrm{\infty }}{lim}\frac{3+\frac{5}{{x}^{2}}}{1+\frac{1}{{x}^{2}}}$
$=\frac{3+\frac{5}{\mathrm{\infty }}}{1+\frac{1}{\mathrm{\infty }}}$
$=\frac{3+0}{1+0}$
$\underset{x\to \mathrm{\infty }}{lim}\frac{3{x}^{2}+5}{{x}^{2}+1}=3$
Jeffrey Jordon | 2023-03-24 16:53:17 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 7, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.7360167503356934, "perplexity": 1888.262331608502}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945287.43/warc/CC-MAIN-20230324144746-20230324174746-00210.warc.gz"} |
https://mathspace.co/textbooks/syllabuses/Syllabus-1007/topics/Topic-20218/subtopics/Subtopic-266154/?textbookIntroActiveTab=overview&activeTab=interactive | # 4.03 Units of area
## Interactive practice questions
Choose the most appropriate unit of measure for the area of a postage stamp.
Hectares
A
Square centimetres
B
Square metres
C
Hectares
A
Square centimetres
B
Square metres
C
Easy
Less than a minute
Choose the most appropriate unit of measure for the area spanned by a bathroom wall.
It is most appropriate to use square metres (m2) to measure the area of:
It is most appropriate to use square centimetres (cm2) to measure the area of:
### Outcomes
#### 1.3.5
choose and use appropriate metric units of area, their abbreviations and conversions between them
#### 1.3.6
estimate the areas of different shapes
#### 1.3.7
convert between metric units of area and other area units | 2022-01-23 12:14:20 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8187194466590881, "perplexity": 4193.566774144306}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-05/segments/1642320304261.85/warc/CC-MAIN-20220123111431-20220123141431-00415.warc.gz"} |
https://info-servis.net/en/the-measurements-of-a-rectangle-are-12-feet-by-16-feet-what-is-the-area-of-the-smallest-circle-tha.18148.html | Mathematics
# The measurements of a rectangle are 12 feet by 16 feet. What is the area of the smallest circle that can cover this rectangle entirely (so that no part of the rectangle is outside the circle)?
It has the same diameter as the diameter of the triangle (which is 20 ft). The area is $\pi*r^2=100\pi$, about 314.15927 square feet. | 2020-10-19 21:12:15 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8034672737121582, "perplexity": 287.3738285343533}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-45/segments/1603107866404.1/warc/CC-MAIN-20201019203523-20201019233523-00009.warc.gz"} |
http://mathhelpforum.com/differential-geometry/111427-sequence-2-a.html | 1. ## sequence 2
Suppose that $x_n$ is a sequence of real numbers and $M \in R$
with $x_n \leq M , \forall n \in N$
if $x_n \to x$ for some $x \in R$
prove that $x \leq M$
2. Originally Posted by flower3
Suppose that $x_n$ is a sequence of real numbers and $M \in R$
with $x_n \leq M , \forall n \in N$
if $x_n \to x$ for some $x \in R$
prove that $x \leq M$
Suppose that $x>M$.
So in the definition of converence use $\varepsilon = {x - M} > 0$.
3. Originally Posted by flower3
Suppose that $x_n$ is a sequence of real numbers and $M \in R$
with $x_n \leq M , \forall n \in N$
if $x_n \to x$ for some $x \in R$
prove that $x \leq M$
You're welcome for the help in your other thread, by the way. | 2018-02-25 00:32:36 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 20, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9824237823486328, "perplexity": 330.288121233187}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-09/segments/1518891816068.93/warc/CC-MAIN-20180224231522-20180225011522-00090.warc.gz"} |
http://physics.aps.org/synopsis-for/10.1103/PhysRevLett.107.133002 | # Synopsis: Mirror, Mirror in Free Space
A Fabry-Pérot cavity exhibits the same behavior when an atom replaces a mirror.
Electromagnetic fields change with boundary conditions around them. For example, a cavity made up of two end mirrors alters the field inside it.
In a paper in Physical Review Letters, Gabriel Hétet and colleagues at the University of Innsbruck in Austria report an experiment in which one mirror of a cavity is replaced by a barium ion $30$ cm away, trapped in free space by an applied electric field. The presence of the single mirror alters the field around the atom, which also acts like a mirror and coherently reflects incident light. The experiment demonstrates how the presence of the mirror alters the way the atom couples to the laser light and changes the atomic coupling constant. The group observed that the setup behaves just like a simple cavity with two parallel mirrors, called a Fabry-Pérot cavity.
This part-cavity, part-free-space setup—an advance in the field of cavity quantum electrodynamics—can be used for storage and retrieval of single photons from the atom, necessary for quantum communication protocols. – Sonja Grondalski
More Features »
### Announcements
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Theoretical calculations anchor graphene’s simple optical absorption in its two-dimensional structure instead of its cone-shaped energy bands. Read More » | 2017-01-22 16:16:36 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 1, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.4349665343761444, "perplexity": 2442.964961627534}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-04/segments/1484560281450.93/warc/CC-MAIN-20170116095121-00014-ip-10-171-10-70.ec2.internal.warc.gz"} |
http://cms.math.ca/cmb/kw/class%20of%20an%20orbit | Canadian Mathematical Society www.cms.math.ca
location: Publications → journals
Search results
Search: All articles in the CMB digital archive with keyword class of an orbit
Expand all Collapse all Results 1 - 1 of 1
1. CMB 2011 (vol 54 pp. 311)
Marzougui, Habib
Some Remarks Concerning the Topological Characterization of Limit Sets for Surface Flows We give some extension to theorems of Jiménez López and Soler López concerning the topological characterization for limit sets of continuous flows on closed orientable surfaces. Keywords:flows on surfaces, orbits, class of an orbit, singularities, minimal set, limit set, regular cylinder Categories:37B20, 37E35
© Canadian Mathematical Society, 2015 : https://cms.math.ca/ | 2015-07-02 08:11:32 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.9493281841278076, "perplexity": 7766.961629830244}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2015-27/segments/1435375095423.29/warc/CC-MAIN-20150627031815-00194-ip-10-179-60-89.ec2.internal.warc.gz"} |
https://www.khanacademy.org/math/old-ap-calculus-ab/ab-derivative-rules/ab-diff-strategy/a/review-categorizing-functions-for-taking-derivatives | If you're seeing this message, it means we're having trouble loading external resources on our website.
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## AP®︎ Calculus AB (2017 edition)
### Course: AP®︎ Calculus AB (2017 edition)>Unit 3
Lesson 12: Strategy in differentiating functions
# Strategy in differentiating functions
AP.CALC:
FUN‑3 (EU)
Differentiation has so many different rules and there are so many different ways to apply them! Let's take a broader look at differentiation and come up with a workflow that will allow us to find the derivative of any function, efficiently and without mistakes.
Many calculus students know their derivative rules pretty well yet struggle to apply the right rule in the right situation. To alleviate this struggle, we want to learn to quickly categorize functions, know which rule to apply, and even rewrite functions in different forms to make differentiation easier.
For reference, here is a summary of the most common derivative rules:
NameRule
Powerstart fraction, d, divided by, d, x, end fraction, open bracket, x, start superscript, n, end superscript, close bracket, equals, n, dot, x, start superscript, n, minus, 1, end superscript
Sumstart fraction, d, divided by, d, x, end fraction, open bracket, start color #11accd, f, left parenthesis, x, right parenthesis, end color #11accd, plus, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, close bracket, equals, start color #11accd, f, prime, left parenthesis, x, right parenthesis, end color #11accd, plus, start color #ca337c, g, prime, left parenthesis, x, right parenthesis, end color #ca337c
Productstart fraction, d, divided by, d, x, end fraction, open bracket, start color #11accd, f, left parenthesis, x, right parenthesis, end color #11accd, dot, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, close bracket, equals, start color #11accd, f, prime, left parenthesis, x, right parenthesis, end color #11accd, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, plus, start color #11accd, f, left parenthesis, x, right parenthesis, end color #11accd, start color #ca337c, g, prime, left parenthesis, x, right parenthesis, end color #ca337c
Quotientstart fraction, d, divided by, d, x, end fraction, open bracket, start fraction, start color #11accd, f, left parenthesis, x, right parenthesis, end color #11accd, divided by, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, end fraction, close bracket, equals, start fraction, start color #11accd, f, prime, left parenthesis, x, right parenthesis, end color #11accd, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, minus, start color #11accd, f, left parenthesis, x, right parenthesis, end color #11accd, start color #ca337c, g, prime, left parenthesis, x, right parenthesis, end color #ca337c, divided by, open bracket, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, close bracket, squared, end fraction
Chainstart fraction, d, divided by, d, x, end fraction, open bracket, start color #11accd, f, left parenthesis, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, right parenthesis, end color #11accd, close bracket, equals, start color #11accd, f, prime, left parenthesis, start color #ca337c, g, left parenthesis, x, right parenthesis, end color #ca337c, right parenthesis, end color #11accd, dot, start color #ca337c, g, prime, left parenthesis, x, right parenthesis, end color #ca337c
We'll be focusing on the last three rules because those are usually the most challenging to apply.
## Spotting products, quotients, and compositions
Most derivative rules tell us how to differentiate a specific kind of function, like the rule for the derivative of sine, left parenthesis, x, right parenthesis, or the power rule.
However, there are three very important rules that are generally applicable, and depend on the structure of the function we are differentiating. These are the product, quotient, and chain rules, so be on the lookout for them. Ask yourself: "Do I see a product, quotient, or composition of functions?"
Product: If you see something like start color #11accd, left parenthesis, x, squared, plus, 1, right parenthesis, end color #11accd, dot, start color #ca337c, sine, left parenthesis, x, right parenthesis, end color #ca337c, you want to notice that this is the product of two functions. From there, you can apply the product rule.
Quotient: Similarly, if you see something like start fraction, start color #11accd, square root of, x, end square root, end color #11accd, divided by, start color #ca337c, cosine, left parenthesis, x, right parenthesis, end color #ca337c, end fraction, you want to notice that one function is being divided by the other, and that the quotient rule will apply.
Composition: Lastly, if you see a function like left parenthesis, 2, x, squared, minus, 4, right parenthesis, start superscript, 5, end superscript, try to think of it as an inner function and an outer function:
start color #11accd, start underbrace, left parenthesis, space, start color #ca337c, start overbrace, 2, x, squared, minus, 4, end overbrace, start superscript, start text, i, n, n, e, r, end text, end superscript, space, end color #ca337c, right parenthesis, start superscript, 5, end superscript, end underbrace, start subscript, start text, o, u, t, e, r, end text, end subscript, end color #11accd
This sort of function is called a composite function, and you can apply the chain rule to find its derivative.
Problem 1
Jake tried to find the derivative of left parenthesis, x, squared, plus, 5, x, right parenthesis, dot, sine, left parenthesis, x, right parenthesis. Here is his work:
\begin{aligned} &\phantom{=}\dfrac{d}{dx}[(x^2+5x)\cdot\sin(x)] \\\\ &=\dfrac{d}{dx}[x^2+5x]\cdot\dfrac{d}{dx}[\sin(x)] \\\\ &=(2x+5)\cdot\cos(x) \\\\ &=2x\cdot\cos(x)+5\cdot\cos(x) \end{aligned}
Is Jake's work correct? If not, what's his mistake?
### Common mistake: forgetting to apply the product or quotient rules
Remember: Taking the product of the derivatives is not the same as applying the product rule.
Similarly, taking the quotient of the derivatives is not the same as applying the quotient rule.
Problem 2
Leon tried to find the derivative of sine, left parenthesis, x, squared, plus, 5, x, right parenthesis. Here is his work:
\begin{aligned} &\phantom{=}\dfrac{d}{dx}[\sin(x^2+5x)] \\\\ &=\dfrac{d}{dx}[\sin(x)\cdot(x^2+5x)] \\\\ &=\dfrac{d}{dx}[\sin(x)]\cdot(x^2+5x)+\sin(x)\cdot\dfrac{d}{dx}[x^2+5x] \\\\ &=\cos(x)(x^2+5x)+\sin(x)(2x+5) \end{aligned}
Is Leon's work correct? If not, what's his mistake?
### Common mistake: Confusing function notation with multiplication
As we saw in Problem 2, start color #11accd, sine, left parenthesis, start color #ca337c, x, squared, plus, 5, end color #ca337c, right parenthesis, end color #11accd is a composite function where the outer function is start color #11accd, sine, left parenthesis, x, right parenthesis, end color #11accd and the inner function is start color #ca337c, x, squared, plus, 5, end color #ca337c. However, some people are confused by the notation and consider this to be the product start color #11accd, sine, left parenthesis, x, right parenthesis, end color #11accd, start color #ca337c, left parenthesis, x, squared, plus, 5, right parenthesis, end color #ca337c. This is an entirely different function, and differentiating it will result in a wrong derivative.
## We can rewrite functions to make differentiation easier.
Let's face it: applying the product, quotient, and chain rules can be a lot of work. The quotient rule is especially demanding. So why would we do all of that work if we don't have to? The following three examples highlight some products and quotients that can be rewritten to make differentiation much easier.
Making expressions more efficient to differentiate isn't just a matter of convenience; The simpler and shorter the differentiation, the smaller the chance that you make a mistake along the way!
### Sometimes, we can rewrite a product as a simple polynomial.
We could apply the product rule to differentiate left parenthesis, x, plus, 5, right parenthesis, left parenthesis, x, minus, 3, right parenthesis, but that would be a lot more work than what's needed. Instead, we can just expand the expression to x, squared, plus, 2, x, minus, 15 then apply the power rule to get the derivative: 2, x, plus, 2.
To really drive home the point, just look at how much more work it would have been to use the product rule:
Product rulePower rule
\begin{aligned}&\phantom{=}\dfrac{d}{dx}[(x+5)(x-3)]\\\\&=\dfrac{d}{dx}[x+5]\cdot (x-3)+(x+5)\cdot \dfrac{d}{dx}[x-3]\\\\&=(1)(x-3)+(x+5)(1)\\\\&=x-3+x+5\\\\&=2x+2\end{aligned}\begin{aligned}&\phantom{=}\dfrac{d}{dx}[(x+5)(x-3)]\\\\&=\dfrac{d}{dx}[x^2+2x-15]\\\\&=2x+2\end{aligned}
To be clear: both ways are correct, but using the power rule will take you less time, and has better chances of avoiding calculation mistakes along the way.
Problem 3
f, left parenthesis, x, right parenthesis, equals, left parenthesis, 3, minus, 8, x, right parenthesis, left parenthesis, 2, x, minus, 7, right parenthesis
How would you rewrite f, left parenthesis, x, right parenthesis so it can be differentiated using the power rule?
### Similarly, some quotient rule problems can be rewritten to use the power rule
We could apply the quotient rule to find the derivative of start fraction, x, start superscript, 6, end superscript, minus, 8, x, cubed, divided by, 2, x, squared, end fraction. However, it would be easier to divide first, getting 0, point, 5, x, start superscript, 4, end superscript, minus, 4, x, then apply the power rule to get the derivative of 2, x, cubed, minus, 4. We just have to remember that the function is undefined for x, equals, 0, and therefore so is the derviative.
If we do it the long way, with the quotient rule, we get the same result. However, we have a better chance to make some kind of mistake along the way.
Not every quotient can be rewritten this way. For example, start fraction, x, squared, plus, 5, x, minus, 14, divided by, x, minus, 7, end fraction cannot be simplified as a polynomial.
Remember: You can always use this method for quotients where the denominator is a monomial.
When the denominator is a polynomial with more than one term, you might be able to simplify it using factorization and canceling common terms.
Don't forget to consider the domain when rewriting quotients.
Problem 4
f, left parenthesis, x, right parenthesis, equals, start fraction, x, start superscript, 5, end superscript, minus, 2, x, cubed, minus, 8, x, squared, divided by, x, end fraction
How would you rewrite f, left parenthesis, x, right parenthesis so it can be differentiated using the power rule?
Assume start text, x, end text, does not equal, start text, 0, end text.
### Last example: rewriting a quotient as a product
For many people, the product rule is easier to remember than the quotient rule is. Fortunately, we can always rewrite a quotient as a product.
Suppose we wanted to differentiate start fraction, square root of, x, plus, 3, end square root, divided by, x, start superscript, 4, end superscript, end fraction but couldn't remember the order of the terms in the quotient rule. We could first separate the numerator and denominator into separate factors, then rewrite the denominator using a negative exponent so we would have no quotients.
\begin{aligned}\dfrac{\sqrt{x+3}}{x^4}&=\sqrt{x+3}\cdot \dfrac{1}{x^4} \\\\ &=\sqrt{x+3}\cdot x^{-4} \end{aligned}
Now we would be ready to use our product rule. (Note: we would also use the chain rule to handle the interior of the square root function.)
Problem 5
h, left parenthesis, x, right parenthesis, equals, start fraction, sine, left parenthesis, x, right parenthesis, divided by, 3, x, end fraction
How would you rewrite h, left parenthesis, x, right parenthesis so it can be differentiated using the product rule?
Want more practice? Try this exercise.
A common struggle: It can be tricky to convert radicals or reciprocals into powers if you're uncomfortable with the process (examples: square root of, x, end square root, equals, x, start superscript, 1, slash, 2, end superscript and start fraction, 1, divided by, x, cubed, end fraction, equals, x, start superscript, minus, 3, end superscript). If you'd like some additional practice with this, check out these exercises:
## Summary
Being fluent at taking derivatives requires knowing which rule to apply and when to apply it. It also requires seeing opportunities to rewrite expressions to make differentiation easier.
Here's a flowchart that summarizes this process:
A flowchart summarizes 2 steps, as follows. Step 1. Categorize the function. The 3 categories are product or quotient, composite, and basic function. Examples of basic functions include x to the n power, sine of x, cosine of x, e to the x power, and natural log of x. If function is a product or quotient, ask the question, can you change the function into another form that's easier to differentiate? If yes, revise the function to something that's easier to differentiate, then go back to step 1. If no, go to step 2. If the function is a composite or basic function, go to step 2. Step 2 is differentiate using the appropriate derivative rule.
## Want to join the conversation?
• Great summary! But the only thing is..isn't this list missing the whole Limit approaching 0 method?
• In general we only use limits when we want to prove something — e.g. to prove that these derivative rules are valid.
Once the rules are proven for a general case there is no need go back to the formal definition of the derivative for specific problems.
• why we need to consider the domain when cancelling the polynomial anyone pls help?
• Suppose y(x) is a rational function defined to be (f(x)*h(x)) / (g(x)*h(x)) where f, g, and h are polynomial functions. When h(x) equals 0, f(x) is undefined. So if we cancel out h(x), we must be sure to exclude the values of x where h(x) = 0 from the domain of y(x).
• Speaking of calculation mistakes - I'm wondering how common they are. How often do you make mistakes when solving problems? To be clear, these are the type of mistakes that you make when you know how to do the work, but accidentally added 3 × 3, or your pencil wrote the opposite of what you were thinking. That kind of mistake.
I counted my errors from the past 20 problems and missed 3, which feels about right. Because I always try to get 100% on everything prior to a unit test, I have spent lots of time going through a 4-problem exercise where I'd keep missing 1 problem then intentionally skipping the others to re-do. I recall spending the most time on trig word problems where you have to model a full function including phase shift.
• what happens to the units of a function when it is differentiated?
• If we take the derivative of a function y=f(x), the unit becomes y unit/x unit.
A derivative is the tangent line's slope, which is y/x. So the unit of the differentiated function will be the quotient.
For example, v(t) is the derivative of s(t).
s -> position -> unit: meter
t -> time -> unit: second
v (ds/dt, the derivative) -> speed -> unit: meter per second
• I noticed there are specific rules for addition, multiplication, and division, but not for subtraction. Would d/dx[f(x)-g(x)] be equivalent to d/dx[f(x)]-d/dx[g(x)]?
(1 vote)
• Yes, the derivative of the difference between two functions is equal to the difference between the derivatives of each function.
• I am confused if we can rewrite the square root of (3 times (cos(x))'s third power) to 3's square root times cos(x)'s 3/2 power, then appply power rule? it is seems different result compared with if firstly apply chain rule to the whole? this is one question in the last "practice", thanks.
(1 vote)
• 𝑑∕𝑑𝑥√(3 cos³𝑥) =
= 1∕(2√(3 cos³𝑥)) ∙ 3 ∙ 3 cos²𝑥 ∙ (−sin 𝑥) =
= −3√3√3 cos²𝑥 sin 𝑥∕(2√3 cos 𝑥 √(cos 𝑥)) =
= −(3√3√(cos 𝑥) sin 𝑥)∕2
𝑑∕𝑑𝑥(√3 ∙ (cos 𝑥)^(3∕2) = √3 ∙ (3∕2) (cos 𝑥)^(1∕2) ∙ (−sin 𝑥) =
= −(3√3√(cos 𝑥) sin 𝑥)∕2
(1 vote)
• are there other rules? this is not all? | 2023-03-24 10:45:40 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 61, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 11, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.5316414833068848, "perplexity": 3123.094235003825}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296945279.63/warc/CC-MAIN-20230324082226-20230324112226-00605.warc.gz"} |
http://www.acmerblog.com/hdu-4067-random-maze-7070.html | 2015
04-16
# Random Maze
In the game “A Chinese Ghost Story”, there are many random mazes which have some characteristic：
1.There is only one entrance and one exit.
2.All the road in the maze are unidirectional.
3.For the entrance, its out-degree = its in-degree + 1.
4.For the exit, its in-degree = its out-degree + 1.
5.For other node except entrance and exit, its out-degree = its in-degree.
There is an directed graph, your task is removing some edge so that it becomes a random maze. For every edge in the graph, there are two values a and b, if you remove the edge, you should cost b, otherwise cost a.
Now, give you the information of the graph, your task if tell me the minimum cost should pay to make it becomes a random maze.
The first line of the input file is a single integer T.
The rest of the test file contains T blocks.
For each test case, there is a line with four integers, n, m, s and t, means that there are n nodes and m edges, s is the entrance’s index, and t is the exit’s index. Then m lines follow, each line consists of four integers, u, v, a and b, means that there is an edge from u to v.
2<=n<=100, 1<=m<=2000, 1<=s, t<=n, s != t. 1<=u, v<=n. 1<=a, b<=100000
The first line of the input file is a single integer T.
The rest of the test file contains T blocks.
For each test case, there is a line with four integers, n, m, s and t, means that there are n nodes and m edges, s is the entrance’s index, and t is the exit’s index. Then m lines follow, each line consists of four integers, u, v, a and b, means that there is an edge from u to v.
2<=n<=100, 1<=m<=2000, 1<=s, t<=n, s != t. 1<=u, v<=n. 1<=a, b<=100000
2
2 1 1 2
2 1 2 3
5 6 1 4
1 2 3 1
2 5 4 5
5 3 2 3
3 2 6 7
2 4 7 6
3 4 10 5
Case 1: impossible
Case 2: 27
/*
// 题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4067
解题报告人：SpringWater
题意描述：
200个点的图，告诉你一些单向边，每条边两个值a和b，表示选与不选的花费。
Sum表示初始图的代价，开始时为0.
（注意图中起点和终点的+1-1的要求）
Sum+费用就是答案。
回头感悟：这题时我acm以来用时最多的一个题目，感觉有些悲剧，不过终于把他拿下来了，还是蛮兴奋的，因为在为了ac它的过程中，
我同时学到了其他很多有关网络流的算法知识，如最小最大网络流求法，有上下界的最小最大网络，最小费用最大流；特别是让人拍案叫绝的
加边法，和让我感叹不已的spfa算法；还有就是发现了Djstla的一个经典局限性，（即对于存在负权边不适用）！不过此题最经典的地方还是
在数学建模上：将此问题转化为一个求最大流；是我觉得最巧妙的地方，原因是：即使求最小费用最大流虽然已经涉及到了很多经典算法，但
是这些方法都已经是 模板了，不足为绝唱（不过就我亲自实现了一番的感觉而言，还是感觉它足以让人累疼，加肉疼！）
*/
#include<iostream>
#include<cstring>
#include<cstdio>
using namespace std;
#define MAXEDGE 54000
#define BREAK 1000000000
struct Edge{
int flow;
int cost;
int point;
}edge[MAXEDGE];
int path[210];
int que[220];
int code[210],num;
int weight[210];
int visit[210];
int in[210],out[210];
int AddEdge(int man,int son,int cost,int flow)
{
code[man]=num;
++num;
code[son]=num;
++num;
return 0;
}
int FindAMinCostWay(int n,int sta,int end)
{
int i,j;
int l,r,temp;
for(i=1;i<=n;i++)
weight[i]=BREAK;
l=0,r=1;
que[0]=sta;
weight[sta]=0;
for(i=que[l];l!=r;i=que[l])
{
{
if(edge[j].flow&&(weight[edge[j].point]>(temp=weight[i]+edge[j].cost)))
{
weight[edge[j].point]=temp;
path[edge[j].point]=j^1;
if(visit[edge[j].point])continue;
que[r]=edge[j].point;
visit[edge[j].point]=1;
++r;
if(r>=200)
r=0;
}
}
++l;
if(l>=200)
l=0;
}
if(weight[end]==BREAK)
return 0;
else
return 1;///这里把我坑害惨了；因为weight[end]==0时也可能满足
} ///，使得返回值即使是0不能排除存在一条最短路径
int main()
{
int T,cas;
int n,m,s,t;
int u,v,a,b;
int end,sta;
int MaxFlow;
int i;
int ans,flow,cost;
freopen("input.txt","r",stdin);
scanf("%d",&T);
for(cas=1;cas<=T;cas++)
{
scanf("%d%d%d%d",&n,&m,&s,&t);
memset(in,0,sizeof(in));
memset(out,0,sizeof(out));
num=0;
memset(code,-1,sizeof(code));
ans=0;
for(i=1;i<=m;i++)
{
scanf("%d%d%d%d",&u,&v,&a,&b);
ans+=(a<b)?a:b;
if(a<b)
else
}
out[t]++,in[s]++;
end=n+2,sta=n+1;
MaxFlow=0;
for(i=1;i<=n;i++)
{
if(out[i]>in[i])
if(out[i]<in[i])
}
flow=0;
while(1)
{
cost=FindAMinCostWay(n+2,sta,end);
if(cost)
{
++flow;
ans+=weight[end];
path[sta]=-1;
for(i=end;path[i]!=-1;i=edge[path[i]].point)
edge[path[i]].flow+=1,edge[path[i]^1].flow-=1;
}
else
break;
}
printf("Case %d: ",cas);
if(MaxFlow==flow)
printf("%d\n",ans);
else
printf("impossible\n");
}
return 0;
}
1. 站长好。我是一个准备创业的互联网小白,我们打算做一个有关国*际*游*学的平台。手上也有了一些境外资源。现阶段的团队现在没有cto.原意出让一些管理股寻找一个靠谱的技术专家做合伙人, 不知道是不是能得到您的帮助。发个帖子或者其他方式。期待您的回应。可以加我微信tianxielemon聊聊。
2. 思路二可以用一个长度为k的队列来实现，入队后判断下队尾元素的next指针是否为空，若为空，则出队指针即为所求。
3. 这道题目的核心一句话是：取还是不取。
如果当前取，则index+1作为参数。如果当前不取，则任用index作为参数。 | 2017-01-20 03:44:22 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.40096142888069153, "perplexity": 3400.6866763171847}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-04/segments/1484560280774.51/warc/CC-MAIN-20170116095120-00517-ip-10-171-10-70.ec2.internal.warc.gz"} |
http://image.absoluteastronomy.com/topics/Angular_eccentricity | Angular eccentricity
Encyclopedia
In the study of ellipse
Ellipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...
s and related geometry, various parameters in the distortion of a circle into an ellipse are identified and employed: Aspect ratio, flattening
Flattening
The flattening, ellipticity, or oblateness of an oblate spheroid is a measure of the "squashing" of the spheroid's pole, towards its equator...
and eccentricity
Eccentricity (mathematics)
In mathematics, the eccentricity, denoted e or \varepsilon, is a parameter associated with every conic section. It can be thought of as a measure of how much the conic section deviates from being circular.In particular,...
.
All of these parameters are ultimately trigonometric functions of the ellipse's modular angle, or angular eccentricity, the conventional denotation being the Greek letter "alpha
Alpha
Alpha is the first letter of the Greek alphabet. Alpha or ALPHA may also refer to:-Science:*Alpha , the highest ranking individuals in a community of social animals...
", .
## Definition
The angular eccentricity of an ellipse with semi-major axis
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
, or transverse radius, , and semi-minor axis
Semi-minor axis
In geometry, the semi-minor axis is a line segment associated with most conic sections . One end of the segment is the center of the conic section, and it is at right angles with the semi-major axis...
, or conjugate radius, , is defined as
## Elliptic parameters
In the following, the previously defined ellipse with radii and will be utilized.
### Aspect ratio
The most tangible characteristic of an ellipse is the diametric quotient of the minor axis to the major axis, the aspect ratio.
{| class="wikitable"
! name !! value in terms of and !! value in terms of
|-
| aspect ratio || ||
|}
### Eccentricity
The eccentricity
Eccentricity (mathematics)
In mathematics, the eccentricity, denoted e or \varepsilon, is a parameter associated with every conic section. It can be thought of as a measure of how much the conic section deviates from being circular.In particular,...
is actually a trio of factors: The primary, or first, eccentricity, , (or just ""), the second eccentricity, , and the third eccentricity, or .
{| class="wikitable"
! symbol !! value in terms of and !! value in terms of
|-
| || ||
|-
| || ||
|-
| || ||
|}
Since they are mostly used in that form anyway, the eccentricities are usually found and kept in their squared form.
The primary eccentricity could be regarded as the complementary aspect ratio, as it is the ratio of the linear eccentricity to the semi-major axis:
### Flattening
The flattening
Flattening
The flattening, ellipticity, or oblateness of an oblate spheroid is a measure of the "squashing" of the spheroid's pole, towards its equator...
, or ellipticity, in contrast, is self-explanatory, as it defines the degree of "squashing", from no flattening (a perfect circle) to complete flattening (a straight line).
{| class="wikitable"
! symbol !! value in terms of and !! value in terms of
|-
| || ||
|-
| || ||
|-
| || ||
|}
While the aspect ratio would seem to be the ideal parameter to find an unknown axis (usually ), it is usually the inverse (primary) flattening that is provided:
## Oblate vs. prolate
If an ellipse is rotated about one of its axes, it sweeps an ellipsoid of revolution. Rotation about the major axis produces a prolate spheroid
Prolate spheroid
A prolate spheroid is a spheroid in which the polar axis is greater than the equatorial diameter. Prolate spheroids stand in contrast to oblate spheroids...
, or prolatum; rotation about the minor axis produces an oblate spheroid, or oblatum.
← Oblate; Prolate →
Rotation causes most large celestial bodies – stars, planets and large satellites – to form oblate spheroids. Planetodetic formulation therefore applies the oblate format, which follows standard elliptic parametrization.
## Applications
For the most part, elliptic formularies ignore the angular eccentricity for the more familiar and notationally concise , , and . However, these parameters don't provide the clear and obvious transformational relationships and structure. Consider the basic elliptic integrand at point P:
While one may consider such ability to convert as just gratuitously frivolous, there is at least one valid reason, as the Binomial series expansion
Binomial series
In mathematics, the binomial series is the Taylor series at x = 0 of the function f given by f = α, where is an arbitrary complex number...
(which planetodetic formularies frequently use) for converges a lot quicker than the one for which, in turn, converges quicker than 's (which—in line with basic, series expansion theory—doesn't even converge when ≥ 1). Friedrich Bessel
Friedrich Bessel
-References:* John Frederick William Herschel, A brief notice of the life, researches, and discoveries of Friedrich Wilhelm Bessel, London: Barclay, 1847 -External links:...
firstly used the notation "n" in 1837 on calculation of meridian arc
Meridian arc
In geodesy, a meridian arc measurement is a highly accurate determination of the distance between two points with the same longitude. Two or more such determinations at different locations then specify the shape of the reference ellipsoid which best approximates the shape of the geoid. This...
length.
Furthermore, as , there are likely other, even more efficient, series expansions possible (if not even efficiently practical approximations to a general transcendental
Transcendental function
A transcendental function is a function that does not satisfy a polynomial equation whose coefficients are themselves polynomials, in contrast to an algebraic function, which does satisfy such an equation...
elliptic integral
Elliptic integral
In integral calculus, elliptic integrals originally arose in connection with the problem of giving the arc length of an ellipse. They were first studied by Giulio Fagnano and Leonhard Euler...
).
Another example is the equation for authalic surface area:
While one certainly can use to define and express this type of equation, using frequently provides a more illustrative—if not even its definitively mathematical—origin. | 2023-01-28 17:07:51 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8128061294555664, "perplexity": 1701.112123002612}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-06/segments/1674764499646.23/warc/CC-MAIN-20230128153513-20230128183513-00245.warc.gz"} |
http://ilzd.org/teaching/2012spring/185-week12.html | 03 Apr 2012
We're going to run through some examples using the Bash shell and some utility programs in Cygwin.
Here are a few of the commands we'll use:
• man: display help information
• cd: change directory
• pwd: print working directory
• ls: list directory contents
• wc: count letters, words, or lines
• cp, rm, mv, touch: copy, remove, move, create/update files
### Filesystem
Cygwin provides a Unix compatibility layer over the Windows filesystem, which gives a single-hierarchy interface rather than a collection of letters for each drive. All real drives (like C, etc.) are found in the virtual directory /cygdrive.
### Globbing
Globbing is the way that Bash refers to multiple files at once (using wildcards). It will often work the same as in the Windows command line, but in the Windows command line globbing is performed by each program (so it can vary from program to program), while the Bash shell performs globbing itself.
### Homework
Work through Exercise 1 & 2 (not to turn in).
To turn in:
1. List the commands you could use to create a directory structure that looks like the hierarchy shown below (with all files empty).
The touch command creates an empty file if the name doesn't already exist.
folder1/
a.txt
b.txt
c.txt
folder2/
a.txt
b.txt
c.txt
folder3/
a.txt
b.txt
2. What command would you use to remove all files starting with a, b, c, or d in your current directory? What happens if there is a subdirectory starting with b in your current directory?
3. The find command is used to locate files (and list the found files). How can you use it in combination with wc to count the number of DLLs in your C drive?
4. The grep command searches through files (or standard input), much like findstr that is usually available in the Windows command line. It uses regular expressions to define a pattern for the search. Suppose you want to print all the lines of a Java program that aren't comments. What command could you use to do that? Assume that commented lines always start with some number of spaces and then the single-line Java comment token (//). Hint: look at the man page for grep to see how to select all lines that don't match a pattern. | 2020-01-23 02:22:30 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.34125396609306335, "perplexity": 2999.2696220465286}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-05/segments/1579250608062.57/warc/CC-MAIN-20200123011418-20200123040418-00313.warc.gz"} |
http://www.sciforums.com/threads/interesting-data-about-inflation-and-millenials-1970-vs-2017.159482/ | # Interesting Data About Inflation and Millenials - 1970 vs 2017
Discussion in 'Business & Economics' started by Kittamaru, Jun 5, 2017.
1. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
So, taking data from the US Census Bureau, USA Today, and other sources:
https://www.census.gov/construction/nrs/pdf/uspricemon.pdf
https://www.usatoday.com/story/mone...action-price-3-kbb-kelley-blue-book/26690191/
http://www.in2013dollars.com/1970-dollars-in-2017?amount=1
In 1970:
Minimum Wage - $2.10 /hr, or$4,368 yearly
Average Wage - $4.52 /hr, or$9,400 yearly
Average New House - $23,450 Average New Car -$3,450
Average Yearly Tuition - 4 year public school - $358 Average Yearly Tuition - 4 year private school -$1,561
In 2017:
Minimum Wage - $7.25 /hr, or$15,080 yearly
Average Wage - $24.97 /hr, or$51,937 yearly
Average New House - $368,300 Average New Car -$33,560
Average Yearly Tuition - 4 year public school - $9,650 Average Yearly Tuition - 4 year private school -$33,480
The difference between 1970 and 2017:
Minimum Wage - 345%
Average Wage - 553%
Average New House - 1,571%
Average New Car - 973%
Average Yearly Tuition - 4 year public school - 2,696%
Average Yearly Tuition - 4 year private school - 2,145%
Now, between 1970 and 2017, the dollar has gone up roughly 630%...
If we just do a straight adjustment for inflation (very rough, but close enough for our purposes:
Minimum Wage - Negative 285%
Average Wage - Negative 77%
Average New House - 941%
Average New Car - 343%
Average Yearly Tuition - 4 year public school - 2,066%
Average Yearly Tuition - 4 year private school - 1,515%
Simply put - the cost of things such as a house, a car, or college tuition has increased many, many times more than wages have.
In 1970 an average car loan with an 11% interest rate and a 3 year repayment term. Now... there are banks offering 72 and 84 month terms. In 1970, a person working minimum wage, 40 hours a week, and paying the national average 9.8% income tax rate could easily get a decent car and have it paid off in two or three years, even sooner if they were careful with their budget (say, $100 a month, or 27.5% of their gross income, they would have a 3500 dollar car paid off in 35 months). Today, a minimum wage worker paying the same percentage of their gross income, would be paying$350 a month, but it would take 96 months to pay off that average $33,560 car... even if they went with a low end car and call it HALF the average price, it's still 48 months). Now, factor in that in 2017, the rough income tax rate for a minimum wage earner is 15%... a six percent increase. It gets even worse when you look at homes. In 1970, a minimum wager worker could, putting 30% of their income towards it, get an average house on a 20 year mortgage; they would be paying about$110 a month and have it paid off in 18 years.
Today, a minimum wage worker putting that same 30% towards it, would be paying about $380 a month, would be paying for 81 years... in order to do a 20 year mortgage, they would have to pay roughly 18,415 a year... which is 122% of their gross income. Ok, lets assume they work two full time minimum wage jobs. That puts them at 30k a year income. They would be paying 61% of their gross income to make a 20 year mortgage. Double the term length, and it would be 30% of their gross income (or about 50% of their net) on a 40 year mortgage, before the interest on the mortgage is even considered. Okay, I hear you saying "but minimum wage isn't supposed to be a living wage". Fine, lets compare average wages: 1970 -$9,399.52 average yearly wage with a $23,450 average house. Putting 30% of that income towards it, they can do a 10 year mortgage and have it paid in 8. Lets make it easier on their budget, and say they put 15% towards it - that gives them a 20 year mortgage, paid in 16 to 17 years. 2017 -$51,937.60 average yearly wage with a $368,300 average house. Putting 30% income towards it, it would take 23.6 years to pay it off... so a 25 year mortgage at least. Even if they get a "cheap" house, at say$200k flat, they would be doing a 15 year mortgage and paying for 13 years... or if they want to make their budget a bit simpler, paying 15% on a 30 year mortgage and paying for 26 years.
Basically, they would be getting almost half the house at twice the cost...
So, simply put... it isn't that millennials are lazy et al... it is that we find ourselves in a financial situation that is, quite simply, untenable.
EDIT - edited to fix LaTeX formatting issue.
sculptor likes this.
3. ### iceauraValued Senior Member
Messages:
25,326
Use medians instead of "averages". You'll get a more directly informative picture, and a more dramatic one. https://www.bls.gov/oes/current/oes_nat.htm
About ten years ago we crossed a line I thought was significant:
starting fifty years ago the median hourly wage in a full time job bought the median house on the standard contract (20% down, 30 year fixed at prevailing rates, 30% of gross income to housing);
the line crossed was this one: it is now the case that in most markets the median job does not rent the median 2-bedroom apartment at the same 30% to housing criterion.
5. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
Aye, it does paint an even more dire picture, doesn't it.
7. ### TiassaLet us not launch the boat ...Staff Member
Messages:
35,062
One of the things about that worth noting actually treads into other issues, as it has to do with argument from privilege. That is to say, what is it about our society that so many business models, and thereby some significant portion of the American economy, that has over the years required workers who cannot afford to live according to the wages paid?
I would not disagree with the point that we can expect someone to raise the issue, but the issue itself, that we have a structure intended to codify laboring (working) poverty, is problematic. The idea of the minimum wage is that people should be able to receive a decent wage for their labor. That the minimum wage is not supposed to be a living wage is the human compromise to inhuman totems such as "The Economy" and "Business". That we should then design business models demanding a perpetually displaced labor class quite clearly describes of the dimensions of a terrible compromise. When I was young, the businessman would speak of jobs and economy and prosperity, and all the good stuff business does. When I was older the businessman explained that actually delivering that stuff was Bad For Business, and, therefore, Bad For The Economy. To a certain degree, cultivating an expanding range of working poor has long been a patriotic duty in these United States.
It is not that I would complain of the observation; rather, I would declare it time to challenge the pretense. I, too, can hear them saying minimum wage isn't supposed to be a living wage, and I call bullshit insofar as the idea that such an argument has merit would seem to beg its own quiver of questions. Thus: If the business model says, "We require the dedicated labor of employees who cannot afford to live in this society", then the business model is dysfunctional.
Quite frankly, I'll try to think of something more useful once I get over this bit.
8. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
Aye, and I agree 100% - if a business cannot pay its workers a livable wage, then said business probably doesn't have any right to exist, much less make huge profits for its owner(s). Hence why I went into the average wage cost as well - there are, unfortunately, too many people who still believe a minimum wage job is ONLY meant for teenagers living with their parents.
9. ### timojinValued Senior Member
Messages:
3,252
Figures on housing , cars , tuition can be challenged.
10. ### originTrump is the best argument against a democracy.Valued Senior Member
Messages:
10,186
OK, then do it.
11. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
Do you wish to challenge them? On what basis - I gave you my sources at the start of the post. Do you take exception to them? If so, on what grounds?
12. ### timojinValued Senior Member
Messages:
3,252
I have been alive worked purchased and sold property purchased new vehicle . and work for living.
13. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
That doesn't answer the questions posed. Try again, or quit trolling.
14. ### dumbest man on earthReal Eyes Realize Real LiesValued Senior Member
Messages:
2,856
If History is to be believed - then nearly every generation has had it more "untenable" than their preceding generations.
Yet, again if History is to be believed, that same History seems to show that those individuals of ANY generation that were willing to put forth the required Hard Work, overcame what others of THEIR generation simply chose to bemoan/complain was "a financial situation that (was)is, quite simply, untenable".
So, Kittamaru, simply put, as in nearly all previous generations - not EVERY member of ANY generation were/are "lazy et al", and some prefer(ed) to work hard to achieve their goals .
And, Kittamaru, to those individuals of ANY generation that were/are willing to put forth the required Hard Work, then NO financial situation was/is, quite simply, untenable.
Last edited: Sep 14, 2017
15. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
Given that I put forth the effort to compile a not insignificant bit of data to support my position, then certainly it isn't too much to ask that you do the same to support yours?
16. ### birchValued Senior Member
Messages:
4,881
sometimes, I wonder if something is in the water. who is going to be at the mcdee's drive-thru to hand you your happy meal? or serve your latte at starbucks? or sew your sneakers in a sweatshop?
How about when all these menial jobs which don't or barely sustain a living are taken over by robots, then people can self-actualize and put forth the hard work to overcome (dirty or menial work society needs and wants done). otherwise it's really unrealistic to blame people when they are not in control of the economy.
why don't pure capitalists just say the truth (as if it's not obvious anyways) and that not everyone is supposed to overcome untenable financial situations, simply because someone has to fill them. it's all about who can grasp the prize, right? otherwise, unless all wages become 'tenable', your point isn't valid and only by omission can it be true; that omission is a whole swath of society that is struggling financially because of lower pay or do you scream at the janitor who scrubs the toilets at your place of business that they didn't overcome whilst you still need someone to do the very thing you are deriding them for? is that rocket science?
otoh, you might have a point. maybe the entire next gen should just go straight to college all the way to a phd, then seek employment commensurate to that attainment level. that would change society wouldn't it? I guess Rumpelstiltskin or santa claus and his elves will do the rest.
the problem isn't the jobs as there are varying people with different skillsets and abilities but the real issue is the pay. a decent living wage should be default. I also think no one should be homeless or without medical care.
I think when society takes care of these problems, it will be a leap forward in human evolution.
Last edited: Sep 15, 2017
17. ### billvonValued Senior Member
Messages:
13,233
I have to disagree with your analysis here on cars. Average price for cars is a very poor indicator of affordability. Why should a poor person care what the cost of a 2017 McLaren P1 is? (3.7 million in case you were wondering) He doesn't - he cares about the cost of the CHEAPEST car out there. Let's compare the cheapest car back then (the venerable VW Beetle) to the cheapest car today (a Nissan Versa.)
Cost of a VW Beetle in 1970 - 2294 (14,607 in 2017 dollars)
Cost of a Nissan Versa in 2017 - 12,885
So about 2000 cheaper in 2017 dollars. Plus which, of course, the Versa is an infinitely better car - better gas mileage (31 vs 23) much better engine (109 vs 34HP) safer, cleaner, more stuff (radio etc.) And much more likely to keep you alive in a crash.
Last edited: Sep 15, 2017
18. ### timojinValued Senior Member
Messages:
3,252
You don't have any statistical data on cars, you don't have data on tuition , according to your opening , so don't try to intimidate me. And on housing I wonder how did they sample and what region of the USA
A small town house in the suburb of Chicago in the late 1970 $40.000 in a higher grade$ 60,000
Dodge Duster 1976 $2800. I paid$ 21.00 per credit hour for 120 credit hours for graduation ,I paid for my son at IIT at 2012 for 4 year to 2017, \$12.600/ year in medical school at Uni. Illinois 49.500/ year . So this are my facts what are your
19. ### dumbest man on earthReal Eyes Realize Real LiesValued Senior Member
Messages:
2,856
So, in that same vein :
- http://www.in2013dollars.com/1776-dollars-in-2017?amount=1
- http://247wallst.com/investing/2010/09/16/the-history-of-what-things-cost-in-america-1776-to-today/
Seeing as how the various aspects of the Economy of the U.S. is(or is failed to be!?) managed/controlled/policed - there will continue to be ups and downs of varying degrees and and lengths of duration...is that not a given?
Seeing as how different individuals within each Generation have various levels of understanding of that Generations True Economic Workings(?) and the various Ideals, Abilities and Work Ethos of those different individuals, would it not be fair to say those individuals of ANY generation that were/are willing to put forth the required Hard Work, then NO financial situation was/is, quite simply, untenable...is that not a given?
Sorry, birch, but I find nothing in the ^^above quoted^^ to be anything near to the point I was trying to put forth.
In all actuality, what you Posted, in my eyes at least, is part of the reason that the U.S. Economy suffers from such highs and lows : the various cognitive abilities of any individual within any Generation and the Overt Determination and Willingness by the "Providers" in each Generation to abuse/take advantage of those various cognitive abilities in the "Consumers".
i.e. : convince everyone to Overpay for to "go straight to college all the way to a phd", when it is common knowledge (that to continue to succeed in perpetuating the U.S. Economy!) :
"that not everyone is supposed to overcome untenable financial situations, simply because someone has to fill...these menial jobs which don't or barely sustain a living...be(ing) at the mcdee's drive-thru to hand you your happy meal? or serve your latte at starbucks? or sew your sneakers in a sweatshop?"
20. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
So... I used corroborating data from multiple sources, including the United States Census Bureau with several tens (if not hundreds) of thousands of data points...
And you wish to throw that all out in favor of your own singular experience.
Why in the world should I bother to take you seriously? Where are my facts? Right there, in front of your face... I provided the links to the sources. Go read something... it may save you making a fool of yourself.
21. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
Fair enough, though I don't believe they included supercars and the like in their averages:
Granted, without a more comprehensive analysis of what they actually looked at, I cannot say that for certain. If you have additional or more comprehensive data sources you would like to include, I'd be more than happy to work them in when time permits.
22. ### KittamaruNever cruel nor cowardly...Staff Member
Messages:
13,666
So you take umbrage with my using actual data compiled by groups with access to far greater pools of data than I, as an individual, could ever hope to accomplish on my own... interesting.
So what, exactly, is your claim, then? That the last 30 years of data should be dumped because it wasn't policed forcibly enough?
I think the data makes it obvious that it isn't a given. As an example (this one from our neighbors to the North):
https://www.forbes.com/sites/jmaure...and-the-recession-isnt-to-blame/#85f751a5946e
and
The forbes article references this report:
https://beta.theglobeandmail.com/gl...15638656/?ref=http://www.theglobeandmail.com&
Another report
https://beta.theglobeandmail.com/gl...10327284/?ref=http://www.theglobeandmail.com&
It isn't just a US trend.
23. ### birchValued Senior Member
Messages:
4,881
Part of the issue is also that many have baccalaureate than ever before but it doesn't really indicate ability by itself. This is why many go for their masters or doctorate to differentiate themselves from the rest of the pool.
Even when I was in the military and during AIT, there were several who had bachelor's degrees but they weren't anymore intelligent than the rest of the class. In fact, most of them were not anywhere near the top of the class and it's easy. one has to consider what the degree is in. they had degrees in sociology or psychology which is easy. I knew this one girl who had a degree in sociology and she always failed the written answer part of the exams because it tests for info retainment and comprehension. Same thing when I went to AIT for network tech, some had degrees in basketweaving but that's a matter of just getting the degree. It's no indication of real ability or skill than joe-blow down the street with no degree. Of course, these were not top-rated schools either but even with that, it's not a guarantee.
One of the positive aspects of this is that more and more professions require actual skills, not just a piece of paper. The more technical the degree, the more likely it's an indication of proficiency.
Just like if you have a law degree, you still can't practice law without passing the bar exam etc. this is why I think the civilian sector should inplement some aspects of the military because it tests for real knowledge, ability and even personality tests to gauge a more comprehensive analysis of what a person is best suited for and there are quite a few options even with these types of tests. | 2018-03-21 12:53:06 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.27459627389907837, "perplexity": 3075.147807493361}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2018-13/segments/1521257647649.70/warc/CC-MAIN-20180321121805-20180321141805-00753.warc.gz"} |
https://physics.stackexchange.com/questions/89223/how-is-the-water-meniscus-at-the-edge-of-a-capillary-tube | # How is the water meniscus at the edge of a capillary tube?
Suppose we have a capillary tube in which water can rise to a height of x cm. If we dip the tube such that the height above the surface is less than x, then how will the water meniscus be at the edge of the tube? Why?
Excuse the flat water at the surface near the base of the capillaries.
EDIT: @NewAlexandria Here's my reasoning.
A is the most likely case as once the water molecules at the inner circumference reach the edge, they cannot go any further up as there is no glass to give the needed normal reaction (cosine component). That's all I can think of.
The formula for capillary rise that most people know is easily derived through a pressure balance between the capillary pressure and the hydrostatic pressure. The hydrostatic pressure equals $$\Delta P_h=\rho g h$$ whereas the capillary pressure is $$\Delta P_c=\frac{2\gamma}{R}=\frac{2\gamma \cos \theta}{r}$$ So balancing these we get our 'famous' equation: $$h=\frac{2\gamma\cos\theta}{\rho g r}$$ Now we have a situation in which the height of our tube above the liquid, $h_{max}$ is smaller than $h$. For an equilibrium situation we still need the hydrostatic pressure and the capillary pressure to balance so we plug in the maximum height that we can get, $h_{max}$, and get: $$h_{max}=\frac{2\gamma \cos\theta_p}{\rho g r}$$ Note that I have changed $\theta$ into $\theta_p$ (see figure below), because that is in fact the only thing that can change, all the other parameters are fixed properties of the system.
It is not entirely clear how you define $A$, but if we define $A$ as the situation for which $\theta_p=\theta$ then changing $\theta_p$ would result in a gradual shift from $A$ to $B$ depending on the value of $h_{max}$. In fact, $B$ is the limit for $h_{max}=0$, because $\cos \pi/2=0$, in which case, as pointed out by Olin and can be seen from the capillary pressure equation, no hydrostatic pressure can be sustained. The fact that $\theta$ can become bigger (i.e. change into $\theta_p$) is caused by contact angle hysteresis at the rim of the capillary tube.
• @OlinLathrop - although I agree that $h_{max}=0$ is a bit of a limiting case – Michiel Dec 8 '13 at 14:42
• @user80551 No, in case B the capillary pressure is 0 because $\cos \pi/2=0$. That is why B can only exist for a tube elevation ($h_{max}$) of 0. To be complete: in case C there will be a negative capillary pressure which would in fact make the liquid level in the tube lower than the surrounding liquid (as is the case for e.g. mercury in a glass tube) – Michiel Dec 8 '13 at 16:04 | 2019-12-06 17:56:25 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.86012202501297, "perplexity": 227.9515138247403}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-51/segments/1575540490743.16/warc/CC-MAIN-20191206173152-20191206201152-00093.warc.gz"} |
http://crypto.stackexchange.com/tags/sha256/new | # Tag Info
1
No, it is not possible to get exactly equal probabilities for a deterministic mapping from all 256-bit numbers to the range 0-99. However, you can ask whether it matters, since a bias on the order of $2^{-256}$ is undetectable. A mapping that took the 256-bit number modulo 100 and refused the inputs less than $2^{256} \bmod 100$ would be unbiased and would ...
5
I agree with the comments that SHA-256 should be fine here. However, if you already use HMAC-SHA-256 for PBKDF2, you could use HKDF Expand, which despite its name is defined even for output lengths shorter than input. In your case the output would be simply: $$\operatorname{HMAC-SHA-256}(\text{key}, \text{info} || \text{0x01}),$$ where 'info' is an ...
-1
You could simply just XOR all the bytes of the hash to one single byte (lets call it $b$ for now): $b = hash_0 \oplus hash_1 \oplus ... \oplus hash_{31}$. $b \in [0, 255]$. Calculate $b' = b / 2.55$. $b' \in [0, 100]$.
7
If you mean exactly as likely, no, because the number of possible hashes is not a multiple of $100$. This is assuming all the hashes are exactly equally likely. You can come very close just by taking $SHA256 hash \pmod {100}$ This will be within one part in $\frac {2^{256}}{100}$, which is a very small number. If you want truly equal, check that the hash ...
0
All the arithmetic in SHA-256 should be 32-bit, it can be implemented at a low level using only 32-bit registers. If you use a representation that can go over 32 bits, then you need to truncate back to 32 bits on every calculation in your chosen language where it will not do so itself - i.e. on every addition.
0
Please review how message authentication codes and HMAC work. They are covered in standard resources (e.g., Wikipedia, crypto textbooks, search on this site). They are just saying that Hashlet can be used to compute a HMAC, which indeed does not encrypt; it provides message authentication.
2
Theoretically, a hash function can be insecure and leak information about the plaintext. In this case knowing multiple hashes will let you make use of weaknesses in any of them. I agree with Dmitry Khovratovich that this isn't likely if you choose hash functions that are considered good, but it is a possibility. More concretely, knowing multiple hash ...
2
No, there is no security decrease in this case. While there could be some hypothetical constructions that might leak the preimage if two images are known, this is definitely not the case for existing hash functions, which are all quite different from each other. An example of such a weak pair of hash functions could be two versions of MD5: one with 63 ...
6
It is possible to turn a hash function into a stream cipher; there are several methods for that, and the simplest is to compute $h(K||IV||x)$ for hash function $h$, initialization vector $IV$, and successive values of a counter $x$. This yields an arbitrarily long sequence of pseudo-random blocks (32 bytes per invocation if $h$ is SHA-256). Then XOR that ...
4
From RFC 5246, section 6.2.3.3: AEAD Ciphers: AEAD ciphers take as input a single key, a nonce, a plaintext, and "additional data" to be included in the authentication check, as described in Section 2.1 of [AEAD]. The key is either the client_write_key or the server_write_key. No MAC key is used. However in RFC 5246, section 5: HMAC ...
Top 50 recent answers are included | 2014-07-11 19:21:53 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3969709277153015, "perplexity": 779.9845891410584}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1404776428772.70/warc/CC-MAIN-20140707234028-00081-ip-10-180-212-248.ec2.internal.warc.gz"} |
https://www.biostars.org/p/9530012/ | 0
0
Entering edit mode
5 weeks ago
Hello I have 700 metagenome assembled genomes that were taxonomically classified using the GTDB database with the GTDB-tk software
So I have taxonomic information assigned for each one of these MAGs but for downstream analysis I need the fasta headers to contain the taxonomic information that GTDB-tk assigned.
This is how the fasta headers of one of the MAGs looks like:
cat cluster1_bin.101.fa | grep '>' | head
> k141_1192826
>k141_94001
>k141_1104537
>k141_375209
>k141_375646
> k141_742386
> k141_560036
> k141_12021
> k141_838926
> k141_1209697
And I want to know if there is a way of extract the full taxonomy of the following table and give it to the respective fasta headers of a MAG:
So this is the desired output for each mag fasta headers using the "cluster1_bin.101.fa" as example
> k141_1192826 Phylum Class Order Family Genus Species
>k141_94001 Phylum Class Order Family Genus Species
>k141_1104537 Phylum Class Order Family Genus Species
>k141_375209 Phylum Class Order Family Genus Species
>k141_375646 Phylum Class Order Family Genus Species
> k141_742386 Phylum Class Order Family Genus Species
> k141_560036 Phylum Class Order Family Genus Species
> k141_12021 Phylum Class Order Family Genus Species
> k141_838926 Phylum Class Order Family Genus Species
> k141_1209697 Phylum Class Order Family Genus Species
any way to do that using any programming language?
MAGs taxonomy fasta • 255 views
0
Entering edit mode
any way to do that using any programming language?
I think this can be done literally in any programming language of your choice. It is a simple fasta header addition which can be done with existing libraries (BioPerl, BioPython), or by using awk/sed to find header lines to which extra information needs to be added. But you will most likely need to write that script on your own.
0
Entering edit mode
Please do not post the images of the data.
0
Entering edit mode
You'll need to post the table in text form for us to be able to help easily. | 2022-08-13 12:14:20 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.17970241606235504, "perplexity": 10092.648487070393}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2022-33/segments/1659882571950.76/warc/CC-MAIN-20220813111851-20220813141851-00431.warc.gz"} |
https://www.acmicpc.net/problem/9396 | 시간 제한 메모리 제한 제출 정답 맞은 사람 정답 비율
1 초 128 MB 0 0 0 0.000%
문제
Flatland is a 2-dimensional world in which some creatures have an odd miserable life. Despite the many handicaps, the poor creatures have recently achieved the wireless technology in Flatland. So, the priest circles (governors of Flatland who kill the apostles of 3D as soon as they see one) created the national motto “Wireless technology is our indisputable right!” and organized a wireless spreading committee for connecting
all important points of the Flatland by wireless antennas.
Everything went well until the committee reached the mountainous region of Flatland. This region can be modeled with a horizontal base line covered by a contiguous serie of mountain. Each mountain is a right-angled isosceles triangle with its base on the base line and its right angle as the peak. Currently, there are only two types of mountains in this region: those with a height of 50, and those with a height of 100. You can see a sample of the mountainous region in the figure below.
The wireless spreading comitte first installed their antennas on the points they had already planned for the mountainous region. But in the end, they found out that a pair of antennas could directly communicate only if the line segment connecting the two antennas had no crossing intersection with any obstacles — specifically the mountains here. Note that two antennas can communicate if only the border of obstacles is on their connecting line segment.
Since removing a wireless antenna in Flatland is nowadays as a deadly sin as “chromatization”, the only way to connect the set of already installed antennas is to install some extra antennas on the appropriate points of the mountains! Wireless antennas can generally relay the messages and connect to ones which cannot communicate directly. In order to reduce the expenses of installing extra antennas, the wireless spreading committee has hired you to find the minimum number of antennas needed to install.
For example, consider the 4 diamond-shaped points in the figure below as the place of the wireless antennas already installed on the mountains. Now the whole set becomes connected if you instal 3 new antennas in the places specified by the circle-shaped points.
입력
There are multiple test cases in the input. Each test case starts with a line containing the integer n (1 ≤ n ≤ 500), the number of mountains, followed by the integer m (1 ≤ m ≤ 10000), the number of already installed antennas. The second line contains n integers h1, h2, . . . , hn (hi ∈ {50, 100}), respectively representing the height of the mountains on the base line from left to right. The third(last) line of the test case contains m integers specifying the position of the antennas already installed on the mountains. The position of each antenna is specified by its X coordinate, assuming the left-most point of the left-most mountain being the origin of the coordinate system. You yourself can calculate the Y coordinate of antenna as it is put on the boundaries of a mountain.
The input terminates with a line of the form ‘0 0’ which should not be processed as a test case.
Note: The Sample Input test case is related to the configuration illustrated in the above figure.
출력
For each test case, write a single line containing the minimum number of extra wireless antennas needed for making the given set of antennas connected.
예제 입력
5 4
100 50 50 100 50
50 220 290 625
0 0
예제 출력
3 | 2017-05-28 22:24:18 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.171239972114563, "perplexity": 1188.6571727128662}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-22/segments/1495463611569.86/warc/CC-MAIN-20170528220125-20170529000125-00054.warc.gz"} |
https://enigmaticcode.wordpress.com/2012/12/12/enigma-1728-problem-tackling/ | Enigmatic Code
Programming Enigma Puzzles
Enigma 1728: Problem tackling
From New Scientist #2895, 15th December 2012 [link]
Joe was in his school’s rugby team. While practising tackling, Joe remembers standing on the goal line 25 feet from his friend Ken, who was by the corner flag. When the master blew his whistle, Ken ran along the touchline and Joe had to try to tackle him. Ken runs at half a mile an hour faster than Joe, who could only manage 12 miles an hour. So Joe never caught up with Ken.
What was the nearest Joe came to Ken?
It is pleasing that Enigma 1728 should be published on 12.12.12, as 1728 = 12³.
[enigma1728]
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14 responses to “Enigma 1728: Problem tackling”
1. Jim Randell 12 December 2012 at 6:05 pm
Assuming I understand they layout of rugby pitches correctly. This is a solution that uses the functions I recently added to enigma.py library to find numerical approximations of functions. (It is implemented using a Golden Section Search minimiser). It runs in 45ms.
from math import sin, cos, tan, radians, sqrt
from enigma import find_min, printf
# convert mph to fps
def fps(s):
return (s * 22.0) / 15.0
# Joe runs at 12 mph
vj = fps(12.0)
# Ken runs at 12.5 mph
vk = fps(12.5)
# min distance for an angle of theta
def min_d(theta):
a = radians(theta)
# distance at time t if J runs at an angle of theta
def d(t):
dk = 25.0 / tan(a) - vk * t
dj = 25.0 / sin(a) - vj * t
return sqrt(dk ** 2 + dj ** 2 - 2 * dk * dj * cos(a))
r = find_min(d, 0.0, 120.0)
return r.fv
r = find_min(min_d, 0.0, 90.0)
printf("min distance = {r.fv} at theta = {r.v}")
Solution: Assuming Joe manages the minimum achievable distance, the closest he comes to Ken is 7 ft.
• Jim Randell 12 December 2012 at 11:17 pm
Here’s a symbolic solution using SymPy.
from sympy import symbols, solve, Rational, sqrt
from enigma import printf
# convert mph to fps
def fps(s):
return s * Rational(22, 15)
# Joe runs at 12 mph
vj = fps(12)
# Ken runs at 12.5 mph
vk = fps(Rational(25, 2))
# distance at time t if J runs at a y velocity of vjy
def d(t, vjy):
ky = vk * t
vjx = sqrt(vj ** 2 - vjy ** 2)
(jx, jy) = (25 - vjx * t, vjy * t)
return sqrt(jx ** 2 + (ky - jy) ** 2)
(t, v) = symbols('t v')
# differentiate the distance
eq1 = d(t, v).diff(t)
# and solve to find when the distance is at a minimum
for r1 in solve(eq1, t):
# so the min distance (for a y velocity of v) is...
eq2 = d(r1, v).simplify()
# so now we need the minimum of that, so we differentiate it...
for r2 in solve(eq2.diff(v), v):
# and find the value for the minimum distance
m = eq2.subs(v, r2)
# and the x,y components of J's velocity
x = sqrt(vj ** 2 - r2 ** 2)
printf("min distance = {m} at vjx/vjy = {q}", q=x/r2)
• Jim Randell 16 January 2013 at 10:46 am
By using the observation that the minimum distance occurs when J is travelling directly towards K, you can deduce the equation for the minimum distance as:
d = 25 / sin(θ) – 24 / tan(θ)
or more generally:
d = g(1/sin(θ) – r/tan(θ))
where r is the ratio vj / vk and g is the initial distance between Joe and Ken.
By differentiation we find this is minimised in the case where cos(θ) = r.
And the solution follows.
2. ahmet sarqcoglu 14 December 2012 at 6:18 pm
hi, can we use any programming language here?
• Jim Randell 14 December 2012 at 7:53 pm
If you’d like to share a programmatic solution, then feel free. In whatever language you choose. (See the “Notes” page for some tips on posting source code in WordPress).
At the moment I tend to post my solutions in Python as I find it lends itself to concise readable code (but then I initially started writing solutions in the somewhat more esoteric Perl), and is freely available on many platforms (and even pre-installed on some), but it’s always interesting to see other languages too, and assuming it’s reasonably self-explanatory I should be able to understand the algorithm.
3. ahmet saracoğlu 15 December 2012 at 12:39 pm
private double ConvertTo(double velocity)
{
return velocity * 5280 / 3600;
}
private void button1_Click(object sender, EventArgs e)
{
double radian = Math.PI / 180, angle = 0, distanceX = 0;
double YKen = 0, YJoe = 0, feet = 0, Vken = 12.5, VJoe = 12, VJx = 0, VJy = 0, t = 0,
difference = 0, min = 25, ang = 0, tmin = 0, distant = 0;
string fortext = "";
TextWriter tw = new StreamWriter("enigma.txt");
// close the stream
Vken=ConvertTo(Vken);
VJoe = ConvertTo(VJoe);
for (angle = 0; angle < 90; angle++)
{
VJx = VJoe * Math.Cos(angle * radian);
VJy = VJoe * Math.Sin(angle * radian);
fortext = fortext +"ANGLE:"+angle.ToString() + "\r\n";
for (distanceX = 0; distanceX <= 25; distanceX+=1)
{
t = distanceX / VJx;
YJoe = VJy * t;
YKen = Vken * t;
difference = Math.Sqrt(Math.Pow((YKen-YJoe),2)+Math.Pow((25-distanceX),2));
fortext = fortext + " TIME PASSED:" + t.ToString();
fortext = fortext + " DISTANCE:" + difference.ToString() + "\r\n";
if (difference < min)
{
distant = distanceX;
min = difference;
ang = angle;
tmin = t;
}
}
}
button1.Text = min.ToString()+ " "+ang.ToString()+" "+tmin.ToString();
tw.WriteLine(fortext);
tw.Close();
}
4. ahmet saracoğlu 15 December 2012 at 5:19 pm
This is the first python program whose belong to me, I have learned today a little
def ConvertTo(velocity):
return velocity*5280/3600
def FindMinDistance(Vken,VJoe):
import math
minumum=25
rdn=math.pi/180 #convert to radian,
Vk=ConvertTo(Vken) #miles/hour is converted to feet/seconds with that function
Vj=ConvertTo(VJoe)
for angle in range(0,89):
Vjx=VJoe*math.cos(angle*rdn)# Joe has velocity at x axis, and this is calculated
Vjy=VJoe*math.sin(angle*rdn)
for distanceX in range (0,25):
t=distanceX/Vjx #Joe is running distanceX feet and time elapsed.
Yjoe=Vjy*t
Yken=Vken*t #Ken's distance to his starting point for 't' time
difference = math.sqrt(math.pow((Yken-Yjoe),2)+math.pow((25-distanceX),2))#Distance between them
if (difference < minumum): minumum = difference
ang = angle# Joe's velocity vector angle
tmin = t
print minumum
• Jim Randell 18 December 2012 at 11:29 pm
I think that’s a good start. Python is fairly easy to pick up (especially if you already know some other programming language), and has relatively few gotchas (although division using the / operator is one of them).
5. arthurvause 17 December 2012 at 11:53 am
Converting the speeds to feet per second, this diagram derives the distance between Joe and Ken.
Then let Wolfram Alpha work out the minimum distance.
6. Hugh Casement 13 June 2016 at 10:08 am
In roughly 4.675 seconds Ken runs 600/7 feet and Joe 24/25 as far.
I think I’m right in saying that if their starting positions (and roles) were reversed, the diagram would be the same triangle. In about 4.87 seconds Ken would run the extra 7, making 625/7 ft = 25/24 times as much as Joe’s 600/7.
Of course it all assumes that rugby players are more intelligent than the dog that always runs directly towards its master: this old dog can’t work out the equation of the pursuit curve. | 2017-06-28 15:40:36 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 1, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.44179418683052063, "perplexity": 8236.537085610891}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 20, "end_threshold": 15, "enable": false}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-26/segments/1498128323711.85/warc/CC-MAIN-20170628153051-20170628173051-00120.warc.gz"} |
https://www.zora.uzh.ch/id/eprint/35153/ | On the length of critical orbits of stable quadratic polynomials
Ostafe, Alina; Shparlinski, Igor E (2010). On the length of critical orbits of stable quadratic polynomials. Proceedings of the American Mathematical Society, 138(8):2653-2656.
Abstract
We use the Weil bound of multiplicative character sums, together with some recent results of N. Boston and R. Jones, to show that the critical orbit of quadratic polynomials over a finite field of q elements is of length O(q(3/4)), improving upon the trivial bound q.
Abstract
We use the Weil bound of multiplicative character sums, together with some recent results of N. Boston and R. Jones, to show that the critical orbit of quadratic polynomials over a finite field of q elements is of length O(q(3/4)), improving upon the trivial bound q.
Statistics
Citations
Dimensions.ai Metrics
12 citations in Web of Science®
14 citations in Scopus® | 2023-03-29 06:23:12 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8996595144271851, "perplexity": 700.4411056518801}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2023-14/segments/1679296948951.4/warc/CC-MAIN-20230329054547-20230329084547-00497.warc.gz"} |
http://icpc.njust.edu.cn/Problem/Pku/1413/ | GIGA Universe Cup
Time Limit: 1000MS
Memory Limit: 10000K
Description
Following FIFA World Cup, a larger competition called "GIGA Universe Cup" is taking place somewhere in our universe. Both FIFA World Cup and GIGA Universe Cup are two rounds competitions that consist of the first round, also known as "group league", and the second called "final tournament." In the first round, participating teams are divided into groups of four teams each. Each team in a group plays a match against each of the other teams in the same group. For example, let's say we have a group of the following four teams, "Engband, Swedon, Argontina, and Nigerua." They play the following six matches: Engband - Swedon, Engband - Argontina, Engband - Nigerua, Swedon - Argontina, Swedon - Nigerua, and Argontina - Nigerua. The result of a single match is shown by the number of goals scored by each team, like "Engband 1 - 0 Argontina," which says Engband scored one goal whereas Argontina zero. Based on the result of a match, points are given to the two teams as follows and used to rank teams. If a team wins a match (i.e., scores more goals than the other), three points are given to it and zero to the other. If a match draws (i.e., the two teams score the same number of goals), one point is given to each. The goal difference of a team in given matches is the total number of goals it scored minus the total number of goals its opponents scored in these matches. For example, if we have three matches "Swedon 1 - 2 Engband," "Swedon 3 - 4 Nigerua," and "Swedon 5 - 6 Argontina," then the goal difference of Swedon in these three matches is (1 + 3 + 5) - (2 + 4 + 6) = -3. Given the results of all the six matches in a group, teams are ranked by the following criteria, listed in the order of priority (that is, we first apply (a) to determine the ranking, with ties broken by (b), with ties broken by (c), and so on). (a) greater number of points in all the group matches, (b) greater goal difference in all the group matches, (c) greater number of goals scored in all the group matches. If two or more teams are equal on the basis of the above three criteria, their place shall be determined by the following criteria, applied in this order: (d) greater number of points obtained in the group matches between the teams concerned, (e) greater goal difference resulting from the group matches between the teams concerned, (f) greater number of goals scored in the group matches between the teams concerned, If two or more teams are still equal, apply (d), (e), and (f) as necessary to each such group. Repeat this until those three rules to equal teams do not make any further resolution. Finally, teams that still remain equal are ordered by : (g) drawing lots by the Organizing Committee for the GIGA Universe Cup. The two teams coming first and second in each group qualify for the second round. Your job is to write a program which, given the results of matches played so far in a group and one team specified in the group, calculates the probability that the specified team will qualify for the second round. You may assume each team has played exactly two matches and has one match to play. In total, four matches have been played and two matches are to be played. Assume the probability that any team scores (exactly) p goals in any match is: 8!/(P!(8 - P)!)*(1/4)^p*(3/4)^(8-p) , for p <= 8, and zero for p > 8. Assume the lot in the step (g) is fair.
Input
The first line of the input is an integer, less than 1000, that indicates the number of subsequent records. The rest of the input is the indicated number of records. A single record has the following format: (empty) (-) (team)1 (-) (team)2 (-) (team)3 (-) (team)4 (team)1 (-) (empty) (-) (m)12 (-) (m)13 (-) (m)14 (team)2 (-) (empty) (-) (empty) (-) (m)23 (-) (m)24 (team)3 (-) (empty) (-) (empty) (-) (empty) (-) (m)34 (team)4 (-) (empty) (-) (empty) (-) (empty) (-) (empty) In the above, (-) is a single underscore (-) and (empty) a sequence of exactly four underscores (____). Each of (team)1,?,(team)4 is either an asterisk character (*) followed by exactly three uppercase letters (e.g., *ENG) , or an underscore followed by exactly three uppercase letters (e.g., _SWE). The former indicates that it is the team you are asked to calculate the probability of the second round qualification for. You may assume exactly one of (team)1,?, (team)4 is marked with an asterisk. Each (m)ij (1 <= i < j <= 4) is a match result between the (team)i and (team)j. Each match result is either __-_ (i.e., two underscores, hyphen, and another underscore) or of the form _x-y where each of x and y is a single digit (<= 8). The former indicates that the corresponding match has not been played, whereas the latter that the result of the match was x goals by (team)i and y goals by (team)j. Since each team has played exactly two matches, exactly two match results are in the former format.
Output
The output should consist of n lines where n is the number of records in the input. The ith line should show the probability that the designated team (marked with an asterisk) will qualify for the second round in the ith record. Numbers should be printed with exactly seven digits after the decimal point. Each number should not contain an error greater than 10^(-7).
Sample Input
5
_____*AAA__BBB__CCC__DDD
*AAA_______0-0__0-0___-_
_BBB_____________-___0-0
_CCC_________________0-0
_DDD____________________
______CHN__CRC__TUR_*BRA
_CHN_______0-2___-___0-4
_CRC____________1-1___-_
_TUR_________________1-2
*BRA____________________
______CMR_*KSA__GER__IRL
_CMR_______1-0___-___1-1
*KSA____________0-8___-_
_GER_________________1-1
_IRL____________________
______TUN__JPN_*BEL__RUS
_TUN________-___1-1__0-2
_JPN____________2-2__1-0
*BEL__________________-_
_RUS____________________
______MEX__CRO_*ECU__ITA
_MEX_______1-0__2-1___-_
_CRO_____________-___2-1
*ECU_________________0-2
_ITA____________________
Sample Output
0.5000000
1.0000000
0.0000000
0.3852746
0.0353304
Source
Japan 2002 Kanazawa | 2020-09-18 20:44:00 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 1, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.38393935561180115, "perplexity": 1345.0497216414822}, "config": {"markdown_headings": false, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2020-40/segments/1600400188841.7/warc/CC-MAIN-20200918190514-20200918220514-00701.warc.gz"} |
https://brilliant.org/problems/factors-and-multiples/ | # Factors and Multiples
Number Theory Level 3
How many positive factors of 36 are multiples of 4? This answer will be x.
What is the sum of ALL of the positive factors of 36? This answer will be y.
× | 2016-10-21 11:25:36 | {"extraction_info": {"found_math": false, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.8885372877120972, "perplexity": 374.5770605783853}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 5, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2016-44/segments/1476988717963.49/warc/CC-MAIN-20161020183837-00554-ip-10-171-6-4.ec2.internal.warc.gz"} |
http://openstudy.com/updates/50aa9925e4b06b5e493315cd | ## Loca4Moca Group Title Solve 5^x + 5 = 9^x one year ago one year ago
i guess it is $5^{x+5}=9^x$ start with $(x+5)\ln(5)=x\ln(9)$ and solve for $$x$$ | 2014-07-22 09:25:57 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6009290218353271, "perplexity": 1533.522449493349}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2014-23/segments/1405997857714.64/warc/CC-MAIN-20140722025737-00204-ip-10-33-131-23.ec2.internal.warc.gz"} |
https://siyavula.com/read/science/grade-10-lifesciences/the-chemistry-of-life/01-the-chemistry-of-life-03 | We think you are located in South Africa. Is this correct?
# Inorganic Compounds
## 1.3 Inorganic compounds (ESG45)
The main focus of this section should be:
• Water: The functions of water in living organisms.
• Minerals: The difference between macro-nutrients and micro-nutrients. The main functions of the essential minerals in animals and plants, and the deficiency diseases.
• Ferilisers: The need for fertilisers, the undesirable consequences of fertilisers (eutrophication) and organic fertilisers.
### The role of water in the maintenance of life (ESG46)
Learn about some of the amazing life-supporting properties of water
Video: 2CMJ
As mentioned in Table 1.1, up to $$\text{65}\%$$ of our bodies are made up of water. Water is an inorganic compound made up of two hydrogen atoms and one oxygen atom. Its molecular formula is $$\text{H}_{2}\text{O}$$. Water plays an important role in the maintenance of biological systems.
Temperature regulation: in humans, the sweat glands produce sweat which cools the body as it evaporates from the body surface in a process called perspiration. In a similar way, plants are cooled by the loss of water vapour from their leaves, in a process called transpiration.
Form and support: water is an important constituent of the body and plays an important role in providing form and support in animals and plants. Animals, such as worms and jellyfish, use water in special chambers in their body to give their bodies support. This use of water pressure to provide body form, and enable movement is called a hydrostatic skeleton . Plants grow upright and keep their shape due to the pressure of water ( turgor pressure) inside the cells.
Transport medium: water transports substances around the body. For example, water is the main constituent of blood and enables blood cells, hormones and dissolved gases, electrolytes and nutrients to be transported around the body.
Lubricating agent: water is the main constituent of saliva which helps chewing and swallowing and also allows food to pass easily along the alimentary canal. Water is also the main constituent of tears which help keep the eyes lubricated.
Solvent for biological chemicals: the liquid in which substances dissolve is called a solvent. Water is known as the universal solvent as more substances dissolve in water than in any other liquid.
Medium in which chemical reactions occur: all chemical reactions in living organisms take place in water.
Reactant: water takes place in several classes of chemical reactions. During hydrolysis reactions, water is added to the reaction to break down large molecules into smaller molecules. Water can also be split into hydrogen and oxygen atoms to provide energy for complex chemical reactions such as photosynthesis.
Temperature Structure and support Lubrication Sweating helps human bodies cool down. Jellyfish and worms use a hydrostatic (water pressure) skeleton to keep their body shape. Water helps maintain the upright structure of plants. Water is an important lubricant in the eye.
Table 1.2: The role of water in living organisms.
### Minerals (ESG47)
Dietary minerals are the chemical elements that living organisms require to maintain health. In humans, essential minerals include calcium, phosphorous, potassium, sulfur, sodium, chlorine and magnesium.
Macro-elements (macro-nutrients) are nutrients that are required in large quantities by living organisms (e.g carbon, hydrogen, oxygen, nitrogen, potassium, sodium, calcium, chloride, magnesium, phosphorus and sulfur).
Micro-elements (micro-nutrients) are nutrients that are required in very small quantities for development and growth and include iron, cobalt, chromium, copper, iodine, manganese, selenium, zinc and molybdenum.
Nutrients required for human health
Table 1.3 below summarises some important minerals required for proper functioning of the human body. Proper nutrition involves a diet in which the daily requirements of the listed mineral nutrients are met.
Mineral Food Source Main Functions Deficiency Disease Macro-nutrients Calcium (Ca) most fruit and vegetables, meat, dairy products strong bones and teeth; muscle contraction; blood clotting; nerve function rickets, osteoporosis Magnesium (Mg) nuts, meat, dairy products strong bones and teeth; nerve and muscle function; energy production osteoporosis, muscle cramps Phosphorus (P) nuts, meat, dairy products strong bones and teeth; nerve function; part of nucleic acids and cell membranes rickets, osteoporosis Potassium (K) bananas, meat, dairy products growth and maintenance, water balance, heart function muscle cramps; heart, kidney and lung failure Sodium (Na) table salt, fruit and vegetables regulates blood pressure and volume; muscle and nerve function muscle cramps Sulfur (S) meat, dairy products, eggs, legumes part of proteins; detoxifies the body; good skin; hair and nails disorder unlikely Micro-nutrients Iron (Fe) meat, legumes part of haemoglobin (the oxygen transport protein); part of some enzymes anaemia Iodine (I) seafood, iodated salt production of hormones by the thyroid gland; strong bones and teeth; good hair; skin and nails goitre, stunted growth, mental problems Zinc (Zn) seafood, meat immune function; male reproductive system stunted growth, prostate problems
Table 1.3: Minerals required by humans.
Nutrients required for plant growth
The previous section examined the key nutrients important for animal growth. In Table 1.4 we will now look at the key nutrients required for plant growth.
Chlorosis is the yellowing of the leaves due to low production or loss of chlorophyll.
Mineral Source Main Functions Deficiency Disease Macro-nutrients Calcium (Ca) inorganic fertilisers; Ca ions in the soil part of the plant cell wall; transport and rention of other elements chlorosis (yellowing of the leaves due to low production or loss of chlorophyll) Magnesium (Mg) inorganic fertilisers; Mg ions in the soil component of chlorophyll (pigment for photosynthesis); activates many enzymes required for growth chlorosis Nitrogen (N) inorganic fertilisers in the form of nitrates; symbiotic nitrogen-fixing bacteria in roots component of chlorophyll; nucleic acids and proteins; seed and fruit production stunted growth; smaller leaves Phosphorus (P) inorganic fertilisers in the form of phosphates; low amounts in the soil photosynthetic process; part of nucleic acids and cell membranes; root growth stunted growth, blue/green leaves Potassium inorganic fertilisers; K ions in the soil needed for protein synthesis, photosynthesis, enzyme activation, opening and closing of stomata; chlorosis; curling leaf tips; brown scorching, poor fruit quality Sulfur (S) inorganic fertilisers protein synthesis; root growth; chlorophyll formation; promotes activity of enzymes chlorosis Micro-nutrients Iron (Fe) inorganic fertilisers; Fe ions in the soil component of the enzyme that makes chlorophyll chlorosis Zinc (Zn) inorganic fertilisers; Zn ions in the soil part of growth-regulating enzyme systems poor leaf growth Sodium (Na) inorganic fertilisers; Na ions in the soil maintains salt and water balance reduced growth Iodine (I) inorganic fertilisers; I ions in the soil needed for energy release during respiration poor growth
Table 1.4: Nutrients required for plant growth.
### Fertilisers (ESG48)
Use of fertilisers
When crops are regularly grown and harvested on the same piece of land, the soil becomes depleted of one or more nutrients. Fertilisers are natural or non-natural mixtures of chemical substances that are used to return depleted nutrients to the soil, improve the nutrient content of the soil and promote plant growth. Inorganic nutrients (such as nitrates and phosphates) are added to the soil in the form of inorganic fertilisers.
Effect of fertilisers on the environment
Using large amounts of fertilisers can be harmful to the environment. Fertilisers wash off into rivers where they are poisonous to plant and animal life. The accumulation of fertilisers in rivers can lead to a process known as eutrophication. This process occurs when excessive nutrients (nitrates and phosphates) from the land (typically from fertilisers) run off into rivers and lakes. This leads to high growth of water plants. Plants grow and produce food by photosynthesis which requires high quantities of oxygen. The high oxygen demand of the rapidly growing water plants removes oxygen available to other organisms in the rivers and lakes. The overgrowth of water plants also blocks sunlight from entering the water, so that plants underwater can no longer photosynthesise and stop producing oxygen. These two processes combine to deplete the water of oxygen and cause aquatic organisms to suffocate and die. The biodegradation of the dead organisms results in a massive increase in bacteria, fungi and algae degrading the dead organic matter, which also require oxygen. This further depletes the available oxygen, and further contributes to the death of fish and other aquatic species.
Figure 1.2: Algae and dead fish in a lake that has undergone eutrophication. Figure 1.3: Algal bloom in a river following eutrophication.
Natural fertilisers: an application of indigenous knowledge systems
The fertilisers discussed above are non-natural inorganic compounds such as nitrates, phosphates etc. However, as a means of reducing the negative impact of the inorganic fertilisers discussed earlier, organic fertilisers that occur naturally can be used. Natural fertilisers consist of organic compounds derived from manure, slurry, worm castings, peat, seaweed etc.
Natural fertilisers supply nutrients to the soil through natural processes such as composting. This means that the nutrients are released back to the soil slowly, and excessive nutrients do not wash off into rivers causing over-fertilisation and eutrophication. However, the use of organic fertilisers is more labour-intensive and the nutrient composition tends to be more variable than the inorganic fertilisers. As a result it is difficult to know for sure whether the particular nutrient required by the plant is actually being supplied by the natural fertiliser.
Figure 1.4: Sample of compost created through processes involving degradation of dead organic matter by bacteria and fungi. Figure 1.5: A homemade compost tumbler. | 2019-01-16 07:59:35 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 1, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.3644770681858063, "perplexity": 9085.528456851202}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.3, "absolute_threshold": 20, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2019-04/segments/1547583657097.39/warc/CC-MAIN-20190116073323-20190116095323-00247.warc.gz"} |
http://www.exambeat.in/aptitude/races-and-games/1710/ | # Aptitude:: Races and Games
@ : Home > Aptitude > Races and Games > General Questions
### Exercise
"
#### In a 100 m race, A can beat B by 25 m and B can beat C by 4 m. In the same race, A can beat C by:
A. 21 m B. 26 m C. 28 m D. 29 m
#### A runs $\dpi{150}&space;1\tfrac{2}{3}$ times as fast as B. If A gives B a start of 80 m, how far must the winning post be so that A and B might reach it at the same time?
A. 200 m B. 300 m C. 270 m D. 160 m
#### In a 300 m race A beats B by 22.5 m or 6 seconds. B's time over the course is:
A. 86 sec B. 80 sec C. 76 sec D. None of these
#### A can run 22.5 m while B runs 25 m. In a kilometre race B beats A by:
A. 100 m B. C. 25 m D. 50 m
#### In a 200 metres race A beats B by 35 m or 7 seconds. A's time over the course is:
A. 40 sec B. 47 sec C. 33 sec D. None of these
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https://digitalcommons.lsu.edu/gradschool_disstheses/6162/ | ## LSU Historical Dissertations and Theses
1996
Dissertation
#### Degree Name
Doctor of Philosophy (PhD)
Chemistry
William H. Daly
#### Abstract
The structures of a number of novel poly(aryl ether) sulfones (nitro, aminomethyl, methyl and ethyl derivatives), which have applications as separation membranes, were determined unequivocally for the first time by applying sophisticated two-dimensional nuclear magnetic resonance (NMR) methods. The degree of substitution (DS) was found to vary among the products from 0.1 percent to about 2 percent (DS: nitro, 2.0; amino, 0.11; aminomethyl, 0.76; methyl, 2.12; ethyl, 2.05). Poly($\gamma$-stearyl-$\alpha$,L-glutamate), PSLG, is a "fuzzy rod" polymer composed of a central backbone that can exist as an $\alpha$-helix. This backbone, a polypeptide, is hydrophilic. The stearyl side chains (the "fuzzy" part of the molecule) are hydrocarbon segments of length C$\sb{18}$. These are hydrophobic, so the rigid-rod is soluble in hydrocarbon solvents, an unusual behavior for such systems. The purpose of this thesis was to look for interactions between the rigid-rod and a random coil polymer, polyethylene (PE). Deuterium NMR data, on samples containing no more than 5 percent deuterated polyethylene (DPE), indicated a small interaction between the two polymers. Differential scanning calorimetry (DSC) identified a transition not found in either blend component, occurring at about 75$\sp\circ$C on cooling and at about 95$\sp\circ$C on heating. Its detection is dependent on the rate of temperature change and occurs near the point where a rapid change in crystallinity is seen in the deuterium NMR. The DSC and NMR work detect a small interaction between the rods and coils. Polarized light and epifluorescence microscopy showed that at low levels of PE (10 percent range), the blends components behave independently. At high PE levels (180 percent), the micrographs show the composites are more than a sum of the parts. There is formation of ordered domains of PSLG, possibly initiated by an interfacial interaction with the overwhelming PE component. The use of dye-labeled PSLG confirmed the identification of these ordered regions as PSLG. For the first time, diffusion of pure PSLG was studied using the fluorescence photobleaching recovery experiment. The results indicated diffusion began near the side-chain melting point of 50$\sp\circ$C.
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COinS | 2017-11-24 22:18:29 | {"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 1, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 0, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0, "katex": 0, "math-container": 0, "wp-katex-eq": 0, "align": 0, "equation": 0, "x-ck12": 0, "texerror": 0, "math_score": 0.6206185817718506, "perplexity": 5827.2657829633445}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "plain"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "warc_path": "s3://commoncrawl/crawl-data/CC-MAIN-2017-47/segments/1510934808972.93/warc/CC-MAIN-20171124214510-20171124234510-00084.warc.gz"} |